Sounds like a ball joint. Take it to an alignment shop with a deal on or free inspections and they can tell you for certain.
a dog
Many causes and different for front wheel drive and rear wheel drive cars. It's hard to say without more detailed information.
Worn front axle and/or front end component.
is it front wheel drive? if so the cv joint is bad
It could be a "CV" joint, wheel bearing, ball joint, strut or any of a number of loose parts. It depends on the type of knocking and how it sounds. In any case, it should be repaired as soon as possible to avoid the possibility of a dangerous condition.
needs new wheel bearings
Its Your CV Joint Or Your Wheel Bearing ........... if it is your cv joint you will hear the knocking or clicking sound especially whilst turning corners.xxxx
wheel bearings?
Probably you have a bad tie rod (maybe both). You can find it on eBay (around $50.00 L&R). Knocking when turning on front wheel drive is most likely the knuckle on the axle. Look at the rubber boot on the end and I will bet it is split.
Assuming it is front wheel or 4 wheel drive, it is worn CV or Constant Velocity Joints. :o)
Could be a wheel bearing, better have it checked out soon before the wheel departs from the vehicle.
Wheel bearing maybe?