Second string and Third-string

Second string noun - A squad of players that are available either individually or as a team to relieve or replace the players who started the game.

Third-string and second string are semantically related. In some cases you can use "Third-string" instead an adjective phrase "Second string".

Second string and third-string are semantically related. Sometimes you can use "Second string" instead the phrase "Third-string" as a noun or an adjective.