1.  howler(n = noun.communication) belly laugh, riot, scream, sidesplitter, thigh-slapper, wow - a joke that seems extremely funny;
is a kind of gag, jape, jest, joke, laugh
Derived form verb howl₄

2.  howler(n = noun.animal) howler monkey - monkey of tropical South American forests having a loud howling cry;
is a kind of new world monkey, platyrrhine, platyrrhinian
is a member of alouatta, genus alouatta
Derived form verb howl₂

3.  howler(n = noun.act) - a glaring blunder;
is a kind of bloomer, blooper, blunder, boner, boo-boo, botch, bungle, flub, foul-up, fuckup, pratfall

1.  One who howls. [1913 Webster]

2.  Any South American monkey of the genus Mycetes. Many species are known. They are arboreal in their habits, and are noted for the loud, discordant howling in which they indulge at night. [1913 Webster]

howler, n.
1 colloq. a glaring mistake.
2 a S. American monkey of the genus Alouatta.
3 a person or animal that howls.

howler monkey