From multi- + collisional. <span class="searchmatch">multicollisional</span> (comparative more <span class="searchmatch">multicollisional</span>, superlative most <span class="searchmatch">multicollisional</span>) Involving multiple collisions...
or pertaining to collisions (especially between particles) collisionality collisionally <span class="searchmatch">multicollisional</span> noncollisional postcollisional precollisional...