dans le dictionnaire PONS
I. ˈunder·ground ADJ
II. ˈunder·ground ADV
III. ˈunder·ground SUBST
under·ground ˈrail·way SUBST
- underground railway
-
underground stream, underground aquifer [ˈækwɪfə] SUBST
- underground stream
-
ground water, underground water SUBST
underground economy SUBST Am DROIT ÉCON
- underground economy
-
underground railway TRANSP COMM
- underground railway
-