Just to add, as it has already been correctly defined........it means continue straight ahead, whatever your position in relation to the marshaller. I add this because I once experienced a (not very popular) training captain who insisted it meant 'come to me'! Where he got this from I don't know. When I challenged him as he kept turning towards the marshaller he informed me of my lack of knowledge of the marshalling signals and continued his incorrect action. Having checked for obstacles to make sure he wasn't going to hit anything my side I again tried to point out why the marshaller was asking him to go straight ahead (ie desist with his right turn) to no avail. We ended up with the nose wheel on the yellow line, the right main gear to the right of the yellow line and, you guessed it, the left main gear to the right of the yellow line too! The german marshaller (it was Koln) chucked his batons in his car, threw his hands in the air and drove off with his wheels spinning.......the training captain then proceded to announce how crap the marshaller was at his job too!
It should be noted that in many parts of the world the marshallers seem unaware of the signals and what they mean. We regularly experience marshallers who just keep giving the straight ahead signal when what they actually want you to do IS to follow the yellow line onto stand. It seems that only experience and knowledge of where these particular types exist is the only way to tell if they actually want you to follow ICAO standards or not.................!!
PP