Having the leading position or higher score in a contest:
— He is ahead by a pawn.

synonyms: in the lead, leading.

At or in the front:
— I see the lights of a town ahead.
— The road ahead is foggy.
— Staring straight ahead.

synonyms: before, in front.

Roget 280: in advance, before, ahead, in the van, in the lead; foremost, headmost^†; in front; at the head, out in front; way out in front, far ahead.   

Roget 303: beyond the mark, ahead.   

Roget 234: before; in front, in the van, in advance; ahead, right ahead; forehead, foremost; in the foreground, in the lee of; before one's face, before one's eyes; face to face, vis-a-vis; front a front.    ... show more

Toward the future; forward in time:
— I like to look ahead in imagination to what the future may bring.

synonym: forward.

In a forward direction:
— Go ahead.
— The train moved ahead slowly.
— The boat lurched ahead.

synonyms: forrader, forward, forwards, onward, onwards.

Roget 282: forward, onward; forth, on, ahead, under way, en route for, on one's way, on the way, on the road, on the high road, on the road to; in progress; in mid progress; in transitu [Lat.] etc. 270.    ... show more

Ahead of time; in anticipation:
— When you pay ahead (or in advance) you receive a discount.
— We like to plan ahead.

synonyms: beforehand, in advance.

To a more advanced or advantageous position.

To a different or a more advanced time (meaning advanced either toward the present or toward the future).

Leading or ahead in a competition:
— The horse was three lengths ahead going into the home stretch.
— Ahead by two pawns.

synonyms: in the lead, out front.