Gum and Sweet gum

Gum noun - Any of various substances (soluble in water) that exude from certain plants; they are gelatinous when moist but harden on drying.

Sweet gum and gum are semantically related. In some cases you can replace phrase "Sweet gum" with "Gum", this terms are similar.

Sweet gum noun - Reddish-brown wood and lumber from heartwood of the sweet gum tree used to make furniture.

Gum and sweet gum are semantically related. You can use "Gum" instead a noun phrase "Sweet gum".