Cotton tail and Cottontail

Cottontail and cotton tail are semantically related. In some cases you can use "Cottontail" instead a noun phrase "Cotton tail".

Cottontail noun - Common small rabbit of North America having greyish or brownish fur and a tail with a white underside; a host for Ixodes pacificus and Ixodes scapularis (Lyme disease ticks).

Cotton tail and cottontail are semantically related. Sometimes you can replace phrase "Cotton tail" with "Cottontail", this terms are similar.