Begin, v. i. [imp. & p. p. Began, Begun; p. pr. & vb. n. Beginning.]
Etymology: [AS. beginnan (akin to OS. biginnan, D. & G. beginnen, OHG. biginnan, Goth., du-ginnan, Sw. begynna, Dan. begynde); pref. be- + an assumed ginnan. sq. root31. See Gin to begin.]
1. To have or commence an independent or first existence; to take rise; to commence. Vast chain of being! which from God began. Pope.
2. To do the first act or the first part of an action; to enter upon or commence something new, as a new form or state of being, or course of action; to take the first step; to start. "Tears began to flow." Dryden. When I begin, I will also make an end. 1 Sam. iii. 12.
2 other Webster entries under this spelling
Begin, v. t.
1. To enter on; to commence. Ye nymphs of Solyma ! begin the song. Pope.
2. To trace or lay the foundation of; to make or place a beginning of. The apostle begins our knowledge in the creatures, which leads us to the knowledge of God. Locke.
Syn. -- To commence; originate; set about; start.
Begin, n.
Beginning. [Poetic & Obs.] Spenser.
Shades of meaning
Fernald lists begin only as an antonym, under cease, die, end.
Where he writes about it:
The Latin commencement is more formal than the Saxon beginning, as the verb commence, is more formal than begin. — from beginning
If we were to speak of the commencement of the Pacific Railroad, we should be understood to refer to the enterprise and its initiatory act; if we were to refer to the roadway we should say "Here is the beginning of the Pacific Railroad." In the great majority of cases begin and beginning are preferable to commence and commencement as the simple, idiomatic English words, always accurate and expressive. — from beginning