Illustrated Glossary of Organic Chemistry

Metalorganic compound: A compound containing both carbon atom(s) and metal atom(s), but lacking a covalent carbon-metal bond.


Lithium acetate lacks a carbon-metal bond
so it is a metalorganic compound.
  
Methyllithium has a carbon-metal bond
so it is not a metalorganic compound, but
instead is an organometallic compound.