在不同地區，一(yi)星(xing)期(qi)的(de)(de)開(kai)始(shi)時間并不完全一(yi)致。許多英(ying)語(yu)國家、猶太(tai)教、日(ri)本是(shi)星(xing)期(qi)日(ri)，埃及人的(de)(de)一(yi)星(xing)期(qi)是(shi)從星(xing)期(qi)六開(kai)始(shi)的(de)(de)。多數歐洲(zhou)國家都以(yi)星(xing)期(qi)一(yi)為一(yi)星(xing)期(qi)的(de)(de)第一(yi)天。而中國大陸習慣上也認為星(xing)期(qi)一(yi)是(shi)開(kai)始(shi)時間。

但(dan)越來越多的英(ying)文(wen)字(zi)典(dian)也開始以星(xing)期一定義為一星(xing)期的第一天，否則(ze)周末(mo)（weekend）這(zhe)個(ge)字(zi)就很難說(shuo)得通。

從(cong)宗教(jiao)的(de)觀點來看，《圣經(jing)》中認為(wei)，上(shang)帝用六天(tian)(tian)創(chuang)造世界(jie)萬物(wu)，在(zai)(zai)(zai)第(di)七天(tian)(tian)休息，這七天(tian)(tian)是(shi)(shi)從(cong)星(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)開(kai)始的(de)，第(di)七天(tian)(tian)是(shi)(shi)星(xing)(xing)期(qi)(qi)六，所(suo)以(yi)猶太教(jiao)以(yi)星(xing)(xing)期(qi)(qi)六為(wei)安息日(ri)(ri)(ri)；在(zai)(zai)(zai)基(ji)督教(jiao)成(cheng)為(wei)古羅馬國教(jiao)后(hou)，因(yin)為(wei)耶穌是(shi)(shi)在(zai)(zai)(zai)星(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)復活(huo)的(de)，所(suo)以(yi)將禮拜日(ri)(ri)(ri)改為(wei)星(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)；伊(yi)斯(si)蘭教(jiao)認為(wei)真(zhen)主(zhu)在(zai)(zai)(zai)第(di)六天(tian)(tian)完成(cheng)創(chuang)造工(gong)作，這一天(tian)(tian)應該慶(qing)祝，所(suo)以(yi)將星(xing)(xing)期(qi)(qi)五定為(wei)重大禮拜的(de)主(zhu)麻(ma)日(ri)(ri)(ri)。

星耀最早在西元七世(shi)紀(ji)就通過不空和(he)尚和(he)楊(yang)景風所(suo)譯《文殊師利菩薩及(ji)諸仙所(suo)說(shuo)吉(ji)兇時(shi)日善惡(e)宿曜經》傳(chuan)入中國。

日(ri)曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)天，月曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)一(yi)，火曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)二，水(shui)曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)三，木曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)四(si)，金(jin)曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)五，土(tu)曜(yao)(yao)日(ri)是(shi)星(xing)(xing)(xing)(xing)(xing)期(qi)六。后(hou)來《宿耀(yao)經》通過(guo)平安時(shi)代的(de)唐朝(chao)留學生(sheng)空海傳(chuan)入日(ri)本，并成為(wei)(wei)日(ri)本宿耀(yao)占(zhan)星(xing)(xing)(xing)(xing)(xing)術或密教占(zhan)星(xing)(xing)(xing)(xing)(xing)術的(de)重要經典，也作(zuo)為(wei)(wei)了(le)沿(yan)用了(le)中(zhong)(zhong)國(guo)(guo)(guo)以七曜(yao)(yao)為(wei)(wei)一(yi)周每日(ri)的(de)稱謂。中(zhong)(zhong)國(guo)(guo)(guo)在(zai)民國(guo)(guo)(guo)成立后(hou)改稱星(xing)(xing)(xing)(xing)(xing)期(qi)日(ri)至六，但在(zai)日(ri)本、韓國(guo)(guo)(guo)和朝(chao)鮮(xian)仍(reng)沿(yan)用此名字。

中文世界教會常以(yi)"禮(li)拜(bai)一(yi)"、"禮(li)拜(bai)二(er)"、…稱呼星(xing)期諸日。受其影響，一(yi)般(ban)民眾也這么用，亦將"禮(li)拜(bai)"一(yi)詞等(deng)于"周"。如"下(xia)周"等(deng)于"下(xia)禮(li)拜(bai)"。

廣東話（廣州(zhou)話）、吳語(yu)(yu)(yu)和閩南話口(kou)語(yu)(yu)(yu)也(ye)以"禮拜一"、"禮拜二"…方式稱呼星期，星期日(ri)則稱為"禮拜日(ri)"，簡(jian)稱"禮拜"。閩南話口(kou)語(yu)(yu)(yu)并(bing)使(shi)用如"拜一"的(de)簡(jian)稱。

古中國日期創制

在我國古代，也有一種跟星期(qi)類似的(de)(de)(de)表示日期(qi)的(de)(de)(de)方式。在距(ju)今3 700年(nian)前的(de)(de)(de)商朝，對農歷(li)進行了(le)修訂(ding)。修訂(ding)后的(de)(de)(de)農歷(li)，平年(nian)12個(ge)月，大(da)月30天(tian)(tian)，小(xiao)月29天(tian)(tian)，閏年(nian)增加(jia)一個(ge)月。同時(shi)為了(le)方便，把一個(ge)月分為4周，大(da)月中有兩周是(shi)(shi)7天(tian)(tian)，兩周是(shi)(shi)8天(tian)(tian)；小(xiao)月中有三周是(shi)(shi)7天(tian)(tian)，一周是(shi)(shi)8天(tian)(tian)。由(you)于這樣的(de)(de)(de)周期(qi)符合月亮的(de)(de)(de)圓缺變化（即朔—上弦(xian)—望—下(xia)弦(xian)—朔……），所以將其稱為"星期(qi)"。

到了(le)漢武帝時期(qi)(qi)，這(zhe)樣的(de)(de)周(zhou)期(qi)(qi)被定為(wei)(wei)(wei)(wei)制定工作(zuo)日(ri)(ri)(ri)、休息(xi)日(ri)(ri)(ri)的(de)(de)依(yi)(yi)據，并且每(mei)天(tian)(tian)(tian)也有(you)了(le)自己(ji)的(de)(de)名稱(cheng)(cheng)。稱(cheng)(cheng)7天(tian)(tian)(tian)的(de)(de)星(xing)(xing)(xing)(xing)期(qi)(qi)為(wei)(wei)(wei)(wei)"平周(zhou)"，8天(tian)(tian)(tian)的(de)(de)星(xing)(xing)(xing)(xing)期(qi)(qi)為(wei)(wei)(wei)(wei)"閏(run)(run)周(zhou)"。"平周(zhou)"前6天(tian)(tian)(tian)為(wei)(wei)(wei)(wei)工作(zuo)日(ri)(ri)(ri)（依(yi)(yi)次稱(cheng)(cheng)為(wei)(wei)(wei)(wei)星(xing)(xing)(xing)(xing)期(qi)(qi)一、星(xing)(xing)(xing)(xing)期(qi)(qi)二(er)、星(xing)(xing)(xing)(xing)期(qi)(qi)三、星(xing)(xing)(xing)(xing)期(qi)(qi)四、星(xing)(xing)(xing)(xing)期(qi)(qi)五(wu)、星(xing)(xing)(xing)(xing)期(qi)(qi)六(liu)），第七天(tian)(tian)(tian)為(wei)(wei)(wei)(wei)休息(xi)日(ri)(ri)(ri)（稱(cheng)(cheng)為(wei)(wei)(wei)(wei)星(xing)(xing)(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)）；"閏(run)(run)周(zhou)"前6天(tian)(tian)(tian)為(wei)(wei)(wei)(wei)工作(zuo)日(ri)(ri)(ri)（名稱(cheng)(cheng)同"平周(zhou)"），后2天(tian)(tian)(tian)為(wei)(wei)(wei)(wei)休息(xi)日(ri)(ri)(ri)（依(yi)(yi)次稱(cheng)(cheng)為(wei)(wei)(wei)(wei)星(xing)(xing)(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)、閏(run)(run)星(xing)(xing)(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)）。到了(le)兩晉南北朝時期(qi)(qi)，這(zhe)種制度有(you)了(le)變動：置閏(run)(run)不(bu)再(zai)以月份為(wei)(wei)(wei)(wei)框架，每(mei)3 400個(ge)星(xing)(xing)(xing)(xing)期(qi)(qi)中(zhong)設1 301個(ge)"閏(run)(run)周(zhou)"，閏(run)(run)日(ri)(ri)(ri)的(de)(de)安(an)排也有(you)一定的(de)(de)變動，閏(run)(run)日(ri)(ri)(ri)放(fang)在(zai)星(xing)(xing)(xing)(xing)期(qi)(qi)幾(ji)之后就叫閏(run)(run)星(xing)(xing)(xing)(xing)期(qi)(qi)幾(ji)。在(zai)"閏(run)(run)周(zhou)"中(zhong)，若閏(run)(run)日(ri)(ri)(ri)是(shi)"閏(run)(run)星(xing)(xing)(xing)(xing)期(qi)(qi)日(ri)(ri)(ri)"則(ze)為(wei)(wei)(wei)(wei)休息(xi)日(ri)(ri)(ri)，否則(ze)為(wei)(wei)(wei)(wei)工作(zuo)日(ri)(ri)(ri)。

古巴比倫日期

公元前(qian)7至6世紀(ji)，巴(ba)比倫人(ren)便有(you)了星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)制。他們(men)把一(yi)(yi)個(ge)(ge)月(yue)分為4周(zhou)，每(mei)周(zhou)有(you)7天(tian)，即一(yi)(yi)個(ge)(ge)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)。古巴(ba)比倫人(ren)建(jian)造七(qi)(qi)星(xing)(xing)(xing)(xing)壇祭祀星(xing)(xing)(xing)(xing)神。七(qi)(qi)星(xing)(xing)(xing)(xing)壇分7層(ceng)，每(mei)層(ceng)有(you)一(yi)(yi)個(ge)(ge)星(xing)(xing)(xing)(xing)神，從上到下依此為日、月(yue)、火、水、木、金(jin)(jin)、土(tu)(tu)7個(ge)(ge)神。7神每(mei)周(zhou)各主管(guan)一(yi)(yi)天(tian)，因此每(mei)天(tian)祭祀一(yi)(yi)個(ge)(ge)神，每(mei)天(tian)都以一(yi)(yi)個(ge)(ge)神來(lai)命(ming)名：太陽(yang)神沙馬什(shen)主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)日，稱(cheng)(cheng)日曜日；月(yue)亮神辛主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)一(yi)(yi)，稱(cheng)(cheng)月(yue)曜日；火星(xing)(xing)(xing)(xing)神涅爾伽(jia)主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)二，稱(cheng)(cheng)火曜日；水星(xing)(xing)(xing)(xing)神納布主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)三，稱(cheng)(cheng)水曜日；木星(xing)(xing)(xing)(xing)神馬爾都克(ke)主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)四，稱(cheng)(cheng)木曜日；金(jin)(jin)星(xing)(xing)(xing)(xing)神伊什(shen)塔爾主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)五，稱(cheng)(cheng)金(jin)(jin)曜日；土(tu)(tu)星(xing)(xing)(xing)(xing)神尼努爾達主管(guan)星(xing)(xing)(xing)(xing)期(qi)(qi)(qi)六，稱(cheng)(cheng)土(tu)(tu)曜日。

古(gu)巴比倫人創立(li)的(de)(de)(de)星(xing)(xing)期制(zhi)，首(shou)先傳(chuan)到古(gu)希臘、古(gu)羅馬等地。古(gu)羅馬人用(yong)他(ta)們自己信仰的(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)的(de)(de)(de)名(ming)字來(lai)(lai)(lai)命名(ming)1周7天：Sun\'s-day（太陽神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Moon\'s-day（月亮神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Mars\'s-day（火星(xing)(xing)神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Mercury\'s-day（水星(xing)(xing)神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Jupiter\'s-day（木(mu)星(xing)(xing)神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Venus\'-day（金星(xing)(xing)神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)），Saturn\'s-day（土星(xing)(xing)神(shen)(shen)(shen)(shen)(shen)(shen)日(ri)）。這7個名(ming)稱傳(chuan)到英國后(hou)，盎格(ge)(ge)魯-撒克遜人又用(yong)他(ta)們自己的(de)(de)(de)信仰的(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)的(de)(de)(de)名(ming)字改(gai)造了其中4個名(ming)稱，以(yi)Tuesday 、Wednesday、Thursday、Friday 分別取代Mars\'s-day 、Mercury\'s-day 、Jupiter\'s-day 、Venus\'-day。 Tuesday來(lai)(lai)(lai)源(yuan)于(yu)Tiu，是(shi)(shi)盎格(ge)(ge)魯-撒克遜人的(de)(de)(de)戰神(shen)(shen)(shen)(shen)(shen)(shen)；Wednesday來(lai)(lai)(lai)源(yuan)于(yu)Woden，是(shi)(shi)最高的(de)(de)(de)神(shen)(shen)(shen)(shen)(shen)(shen)，也稱主神(shen)(shen)(shen)(shen)(shen)(shen)；Thursday來(lai)(lai)(lai)源(yuan)于(yu)Thor，是(shi)(shi)雷神(shen)(shen)(shen)(shen)(shen)(shen)；Friday來(lai)(lai)(lai)源(yuan)于(yu)Frigg，是(shi)(shi)愛情女神(shen)(shen)(shen)(shen)(shen)(shen)。這樣就形(xing)成了今天英語中的(de)(de)(de)1周7天的(de)(de)(de)名(ming)稱：

Sunday（太陽(yang)神(shen)日）

Monday（月(yue)亮神(shen)日）

Tuesday（戰神日）

Wednesday（主神日）

Thursday（雷(lei)神(shen)日）

Friday（愛神日(ri)）

Saturday（土神日）。