Definition of longitudinal adjective from the Oxford Advanced Learner's Dictionary

longitudinal

adjective
ˌlɒŋɡɪˈtjuːdɪnl
 
; ˌlɒndʒɪˈtjuːdɪnl
 
; ˌlɑːndʒəˈtuːdnl
 
; ˌlɔːndʒəˈtuːdnl
 
(technical)
 
1 going downwards rather than acrossThe plant's stem is marked with thin green longitudinal stripes.2 concerning the development of something over a period of timea longitudinal study of ageing3 connected with longitudethe town's longitudinal positionlongitudinally
ˌlɒŋɡɪˈtjuːdɪnəli
 
; ˌlɒndʒɪˈtjuːdɪnəli
 
; ˌlɑːndʒəˈtuːdnəli
 
; ˌlɔːndʒəˈtuːdnəli
 
adverb