1. gather together or accumulate (a large amount or number of valuable material or things) over a period of time: "starting from nothing he had amassed a huge fortune"
▪ (of people) gather together in a crowd or group:"the soldiers were amassing from all parts of Spain"
Word Originlate 15th century: from French amasser or medieval Latin amassare, based on Latin massa ‘lump’ (see mass).