Question: why lord ganesha called ekdant?
Answer: once he came into senses he threw his Pharasaa (axe) at Lord Ganesha. Lord Ganesha directly recognized it as his father's weapon (his father gave it to Parashuraam) and received it with all his humility on his one tusk. ... that's why he's additionally known as Ekdant or Ekdanshtra - suggests that who has only 1 tusk.