Similar design, different roles
Ball joints and tie rod ends both use a ball stud inside a socket. The difference is where they sit and what they do.
A ball joint connects a control arm to the steering knuckle and is part of the suspension. A tie rod end connects the steering linkage to the knuckle and is part of the steering system.
Key specifications for each
Ball joints: mounting style, housing diameter or flange pattern, stud taper and thread, overall height.
Tie rod ends: thread size, pitch and hand, stud taper, overall length.
Why the distinction matters for buyers
Clear classification keeps catalogs accurate and reduces returns. When requesting quotations, list each part under the correct category with its own references.