Definition of: attenuate

(ə·ten′y·āt) v. ·at·ed, ·at·ing v.t.
1. To make thin, small, or fine; draw out, as a wire.
2. To reduce in value, quantity, size, or strength; weaken; impair.
3. To reduce in density; rarefy, as a liquid or gas.
4. Bacteriol. To weaken the virulence of a micro-organism.
—v.i.
5. To become thin, weak, rarefied, etc.
—adjective (a·ten′y·it)
1. Made thin; slender; rarefied; diluted.
2. Bot. Slender and tapering; narrow. [<L attenuatus, pp. of attenuare weaken < ad- + tenuare make thin < tenuis thin]