"Large lagoon" refers to a big body of water that is separated from the ocean by a landmass or barrier. It is a large enclosed area of calm water surrounded by land. Full definition
The fantastic Blue on Blue Resort features one of North Queenslands largest lagoon pools plus a smaller pool located near your apartment. (bestofmagnetic.com)
Large lagoon swimming pool with swim up bar, located on the beach of Palm Cove, opposite playground and patrolled beach. (palmcoveaustralia.com)
Sh 2 - 29, Sh 2 - 31, and Sh 2 - 32 are a group of three nebulae next to the much larger Lagoon nebula. (galaxymap.org)