Co-occurrent is a term used to describe two or more things that occur together at the same time or in the same place. Synonyms for co-occurrent include concurrent, simultaneous, parallel, coincident, concomitant, and accompanying. All of these words imply that two or more events or circumstances are occurring in close proximity to each other and are happening at the same time. Other synonyms for co-occurrent might include contemporaneous, synchronous, joint, and matching. These words all convey a sense of two or more things occurring together - whether they are related or not. When trying to describe events or circumstances that are happening at the same time, it's important to choose the right synonym for the situation.