Trub is a term commonly used in the brewing industry to refer to the sediment or debris that settles at the bottom of beer. However, there are various synonyms that can be used to describe this phenomenon. Some commonly used terms include dregs, lees, sediment, and sludge. In addition, terms like residue, settlings, and particulate matter can also be used to refer to the particles that settle at the bottom of a liquid. While these terms may have slightly different connotations, they all essentially refer to the same thing - the unwanted particles that settle at the bottom of a liquid.