Shouted loudly or yelled, especially to get someone's attention or express strong emotion.
From 'holler,' probably originally from 'hello' or 'hollo' (a hunting call). The term is especially common in American English and originated in the American South.
Before phones existed, people literally had to holler to communicate across distances—hollering was a practical skill. Now it's mostly emotional, and linguists notice that Southern American English preserved this word more than Northern dialects.
Complete word intelligence in one call. Free tier — 50 lookups/day.