Hash mark and Pound sign

Hash mark noun - An insignia worn to indicate years of service.

Pound sign and hash mark are semantically related. In some cases you can replace phrase "Pound sign" with "Hash mark", this phrases are similar.

Pound sign noun - A symbol for a unit of currency (especially for the pound sterling in Great Britain).

Hash mark and pound sign are semantically related. You can use "Hash mark" instead a noun phrase "Pound sign".