thump on front left

on my front left side, i feel a thumping when i turn to the left...it feels like the tire has a knot on it, but it doesn't and when i drive straight or turn right, it seems fine. i think it is a bearing (just a guess), but it is not making a noise or anything.....does anyone have any ideas???????

YIKES! Get that checked out ASAP! Could be a CV joint. Might be a wheel bearing - either way it could be serious. Could also be a ball joint, but given the way it happens I'd first suspect the CV joint. Look under the car and see if the rubber boot covering the CV joint is cracked, worn, or broken. If it is then I'd seriously suspect the CV.