1) Arthropod genus 2) Genus gerris 
Gerris is a bug genus in the family Gerridae (water striders). ===Former species=== ...[software] Gerris is computer software in the field of computational fluid dynamics (CFD). Gerris was released as free and open-source software, subject to the requirements of the GNU General Public License (GPL), version 2 or any later. == Scope == Gerris solves the Navier–Stokes equations in 2 or 3 dimensions, allowing to model industri...
A genus of bugs (hemiptera) with long legs, adapted to resting and moving upon the surface of water of normal surface tension.
[n] - type genus of the Gerrididae
genus Gerris noun type genus of the Gerrididae