nail down

nail down (third-person singular simple present nails down, present participle nailing down, simple past and past participle nailed down)

1. (transitive) to attach with nails

   Nail down the shelf, then paint it.

2. (idiomatic, transitive) to make something (e.g. a decision or plan) firm or certain

   They haven't nailed down their vacation plans yet.

• copperfasten
• pin down

• lain down