Definition of Nodule

Nodule: A small solid collection of tissue, a nodule is palpable (can be felt). It may range in size from greater than 1.0 cm (3/8 inch) to somewhat less than 2 cm (13/16 inch) in diameter. A nodule may be present in the epidermis, dermis or subcutis (at any level in the skin).

The word "nodule" is the diminutive of "node" (a knot or knob) so a "nodule" means "a little knot or knob."