Definition of ageostrophic in English:
ageostrophic
adjective ˌeɪdʒiːəˈstrɒfɪkˌeɪdʒiːəˈstrəʊfɪk
Meteorology Not geostrophic; specifically designating the wind component which when added to a geostrophic wind gives the actual wind.
Origin
1940s. From a- + geostrophic.