1. (noun) an intermediate person; used in the phrase at second hand'

• go-between
• intercessor
• intermediary
• intermediator
• mediator

2. (noun) hand marking seconds on a timepiece

• hand

1. (noun) hand marking seconds on a timepiece

• sweep hand
• sweep-second

1. (adverb) from a source of previously owned goods

• secondhand
• used