Eastern grey squirrel and Tree squirrel

Eastern grey squirrel noun - Common medium-large squirrel of eastern North America; now introduced into England.

Tree squirrel and eastern grey squirrel are semantically related. In some cases you can use "Tree squirrel" instead a noun phrase "Eastern grey squirrel".

Tree squirrel noun - Any typical arboreal squirrel.

Eastern grey squirrel and tree squirrel are semantically related. Sometimes you can replace phrase "Eastern grey squirrel" with "Tree squirrel", this phrases are similar.