commencement

n. 开始，发端；毕业典礼

中文词源

commencement 开始，毕业典礼

来自commence, 开始。引申义毕业典礼，人生的开始。

commencement (n.): late 13c., "beginning," from Old French comencement "beginning, start" (Modern French commencement), from comencier (see commence). Meaning "school graduation ceremony" attested by 1850, American English. (Sense "entrance upon the privileges of a master or doctor in a university" is from late 14c.)
I know what you are thinking of -- the class members grouped in a semicircle on the stage, the three scared boys in new ready-made black suits, the seventeen pretty girls in fluffy white dresses (the gowns of the year), each senior holding a ribbon-tied manuscript bulging with thoughts on "Beyond the Alps Lies Italy," "Our Ship is Launched -- Whither Shall it Sail?" and similar topics. [Charles Moreau Harger, "The Real Commencement," "New Outlook," May 8, 1909]

2. Would passengers please put out cigarettes before the commencement of the flight.: 请乘客在飞机起飞前熄灭香烟.

4. All applicants should be at least 16 years of age at the commencement of this course.: 申请修读这门课程者至少要年满16岁。

5. 'Commence,'was Monsieur Defarge's not unreasonable reply,'at the commencement.': “ 从开头说起, ” 德伐日的回答不无道理.