Definition of "troopship"

[…] the Duke of Rothesay and the Duke of York, however, are serving as troopships to and from Harwich, and it is unlikely that they will be released for some time to come.

1946 May and June, “Notes and News: Anglo-Irish Steamship Fleets”, in Railway Magazine, page 185

The former, on the other hand, would put his troopships safely out of its reach.

1990, Peter Hopkirk, The Great Game, Folio Society, published 2010, page 65