tan (Hebrew #8565)
a monster (as preternaturally formed), i.e. a sea-serpent (or other huge marine animal); also a jackal (or other hideous land animal)
KJV usage: dragon, whale. Compare 8577.
Pronounce: tan
Origin: from an unused root probably meaning to elongate
tanniyn (Hebrew #8577)
intensive from the same as 8565; a marine or land monster, i.e. sea-serpent or jackal
KJV usage: dragon, sea-monster, serpent, whale.
Pronounce: tan-neen'
Origin: or tanniym (Ezek. 29:3) {tan-neem'}