take a solid, often a pellet of insoluble stuff that you’ve gotten from spinning down (centrifuging) a mixture to separate the liquid from the insoluble stuff, add a fresh liquid (e.g. a buffer) and disperse the solid throughout that new liquid, often by pipetting up and down and/or vortexing it (using a fast-shaking-platform-thing to help break things up). This term comes up during the harvesting of bacterial or insect cells we’ve used to express (make) proteins for us. We grow the cells in liquid food (media) and then we spin the cell/media mixtures down to pellet out the cells, pour off the media, and add a nice clean buffer (pH-stabilized salt water) and resuspend the pellet in this liquid before freezing it.