Definition of "Understand" :
verb: know and comprehend the nature or meaning of
"She did not understand her husband."
verb: perceive (an idea or situation) mentally
"I don't understand the idea."
verb: believe to be the case
"I understand you have no previous experience?."
verb: make sense of a language
"She understands French."
verb: be understanding of
"You don't need to explain--I understand!."