It is possible to get confused between the apparently different types of trimmer or Brushcutter that are available.
In reality, most of these distinctions are manufacturers terms, as some companies refer to grass strimmers as line trimmers (as they use a spinning nylon line to cut through grass).
All these terms - grass trimmers, garden trimmers, line trimmers, garden strimmers - generally mean the same thing.
‘Strimmer’ is just a shortened version of ‘grass trimmer’ that has become widely acceptable as a term in itself. All of the above machines use a version of a nylon line to trim patches of grass or neaten the edges of lawns and borders.
There is, however, a difference between all these terms and Brushcutters. Brushcutters do not just use a line but usually have a metal blade as well, either included, or available as an option for heavier work like clearing thick weeds, nettles, briars and so on.