What is "nail down"

vb. 1 (context transitive English) to attach with nails 2 (context idiomatic transitive English) to make something (e.g. a decision or plan) firm or certain

1. v. succeed in obtaining a position; "He nailed down a spot at Harvard" [syn: nail, peg]

2. define clearly; "I cannot narrow down the rules for this game" [syn: pin down, peg down, narrow down, narrow, specify]

3. make final; put the last touches on; put into final form; "let's finalize the proposal" [syn: finalize, finalise, settle]