Adjective
(physics, of an interaction, or of the transfer of energy) That does not involve a collision between particles, bodies, plasmas or waves.
(computing theory) Without the possibility of data packets colliding on the network.
A token ring network is collisionless, but an Ethernet network is not.
(computing theory) Without the possibility of items having the same value, which would prevent reliable lookup.
a collisionless hash
The most important difference is that in the absence of field line breaking, the magnetic field is tied to the electrons and not to the bulk fluid. citation ; Collisionless : MHD is also often used for collisionless plasmas. Source: Internet
The structure of the cosmic microwave background anisotropies is principally determined by two effects: acoustic oscillations and diffusion damping (also called collisionless damping or Silk damping). Source: Internet