Name the suffix that indicates word is describing a cell?

The suffix that indicates a word is describing a cell is -cyte.

Here are some examples:

* Leukocyte: A white blood cell

* Erythrocyte: A red blood cell

* Myocyte: A muscle cell

* Neuron: A nerve cell (although it doesn't strictly end in "-cyte", it's derived from the Greek word "neuron", meaning "nerve")