Segundou is a Brazilian internet word for Monday, built from segunda-feira and used online to mark the start of the week, often with humour about going back to work or school. Clips tagged with it circulate as short reaction sounds for Monday posts, stories and videos, where the shared joke is that Monday itself is the worst part. Because the feeling is universal and the word is instantly recognisable to Portuguese-speaking audiences, the sound keeps appearing at the start of each week, especially on Mondays when creators look for a quick, relatable opener.