What does alter mean?
The definition of alter
Al”ter, v. t.
[imp. & p. p. Altered; p. pr. & vb. n. Altering.] Etym: [F. altérer, LL. alterare, fr. L. alter other, alius other. Cf. Else, Other.]

1 To make otherwise; to change in some respect, either partially or wholly; to vary; to modify. “To alter the king’s course.” “To alter the condition of a man.” “No power in Venice can alter a decree.” Shak. It gilds all objects, but it alters none. Pope. My covenant will I not break, nor alter the thing that is gone out of my lips. Ps. lxxxix. 34.
2 To agitate; to affect mentally. [Obs.] Milton.
3 To geld. [Colloq.]

Synonyms
— Change, Alter. Change is generic and the stronger term. It may express a loss of identity, or the substitution of one thing in place of another; alter commonly expresses a partial change, or a change in form or details without destroying identity.

Al”ter, v. i.
To become, in some respects, different; to vary; to change; as, the weather alters almost daily; rocks or minerals alter by exposure. “The law of the Medes and Persians, which altereth not.” Dan. vi. 8.