In basketball, a rule violation in which a player takes too many steps with the ball in hand without dribbling. The German term for it is 'Schrittfehler' (traveling violation).
example
Der Schiedsrichter pfiff wegen eines Travels und gab der anderen Mannschaft den Ball.
The referee blew the whistle for a travel and gave the ball to the other team.
Usage tips
Register: basketball jargon
'Travel' is an English loanword that is used almost exclusively in the context of basketball as a technical term. It is part of sports jargon.
EXAMPLE
Der Kommentator erklärte die Regel, nachdem der Schiedsrichter auf Travel entschieden hatte.
The commentator explained the rule after the referee called a travel.
Typical verbs
In the context of a game, a travel is 'begangen' (committed) or 'gemacht' (made) by a player. The referee 'pfeift' (whistles for) a travel or 'entscheidet auf' Travel (calls a travel).
EXAMPLE
Der junge Spieler war nervös und beging gleich zu Beginn ein Travel.
The young player was nervous and committed a travel right at the beginning.
Grammar note
Although it is an English word, 'Travel' is treated as a neuter noun in German. So you say 'das Travel' (the travel).
EXAMPLE
Der Trainer ärgerte sich über das unnötige Travel seines Spielers.
The coach was annoyed about his player's unnecessary travel.