From Longman Business Dictionary
palmtoppalm·top /ˈpɑːmtɒpˈpɑːmtɑːp, ˈpɑːlm-/ (also palmtop computer) noun [countableC]COMPUTING a very small computer which can be carried in your pocket or a small bagSYN LAPTOP, NOTEBOOKCompared to full-size computers, palmtops are extremely limited.