The Dutch word for afternoon is
namiddag

Dutch Definition

afternoon
1. namiddag

namiddag	©
1. n-m. (Belgium) afternoon, between 12 and 6 o'clock
In België is het warmer in de namiddag. - In Belgium, it's warmer in the afternoon.
Ik heb een afspraak in de namiddag. - I have an appointment in the afternoon.
Kinderen spelen buiten in de namiddag. - Children play outside in the afternoon.
2. n-m. (Netherlands) late afternoon, between 4 and 6 o'clock
In Nederland wordt de namiddag als de late namiddag beschouwd. - In the Netherlands, the late afternoon is considered as the namiddag.
Het licht is zachter in de namiddag. - The light is softer in the late afternoon.
Veel mensen gaan wandelen in de namiddag. - Many people go for a walk in the late afternoon.