Agaric and Jack-a-lantern

Agaric noun - A saprophytic fungus of the order Agaricales having an umbrellalike cap with gills on the underside.

Jack-a-lantern and agaric are semantically related. In some cases you can replace phrase "Jack-a-lantern" with "Agaric", this terms are similar.

Jack-a-lantern noun - A large poisonous agaric with orange caps and narrow clustered stalks; the gills are luminescent.

Agaric and jack-a-lantern are semantically related. You can use "Agaric" instead a noun phrase "Jack-a-lantern".