IPA: //ˈkɒŋɡrɪɡənt//
KK: /kɒŋˈɡrɛɡənt/
A person who is part of a group that comes together, especially for religious services or worship.
The congregant listened attentively during the sermon.
Congregant is formed from "con-" (meaning together) and "gregare" (meaning to gather). The word refers to a person who gathers together with others, especially in a religious context.
Think of people coming 'together' ('con-') to 'gather' ('gregare') for a common purpose, which is why a congregant is someone who gathers with others.