adjective

1. coming next after the first in order of place or time; 2d or 2nd
2. another; other; additional; supplementary to take a second helping
3. being of the same kind as another; resembling a given original a second Shakespeare
4. alternate; other every second day
5. next below the first in rank, power, value, merit, excellence, etc.
6. inferior; subordinate; secondary
7. Music
   1. lower in pitch
   2. playing or singing a part that is lower in pitch

Etymology: ME secunde < OFr < L secundus, following, second < sequi, to follow: see sequent

noun

1. the next after the first
2. any person, thing, class, place, etc. that is second
3. an article of merchandise that falls below the standard set for first quality
4. 1. a kind of coarse flour
   2. bread made from this
5. an aide or official assistant, esp. to one of the principals in a duel or boxing match
6. the second forward gear of a transmission: it provides more speed but less torque than first
7. the act or an instance of seconding
8. a second helping of something to eat
9. ☆ Baseball second base
10. Music
    1. the second tone of an ascending diatonic scale, or a tone one degree above or below any given tone in such a scale
    2. the interval between two such tones, or a combination of them
    3. the second part in a harmonized composition, esp. the alto
    4. an instrument or voice taking this part

transitive verb

1. to act as an aide or second to; aid; assist
2. to give support or encouragement to; further; reinforce
3. to indicate formally one's approval or support of (a motion, nomination, etc.) as a necessary preliminary to discussion of or a vote on it

adverb

1. in the second place, rank, group, etc.
2. next to or next after the second last row