A carry bag is a handy bag used to carry things.
Spock used a carry bag to hold his clothing when he took a trip through time to save his younger self from death. The bag and clothing were provided by the Enterprise's wardrobe section. (TAS: "Yesteryear")
Amongst Uhura's possessions in an alternate reality version of her Starfleet Academy living space could be seen what appears to be a Starfleet branded carrying bag.