Terminology check in 2D representation: Is a keyway a circumferential groove cut around the diameter of a shaft, often where it changes diameter, or is that description incorrect for a keyway?

Introduction / Context:
Mechanical drawings rely on precise terms. A keyway is an axial slot cut along a shaft to accept a key that prevents relative rotation between the shaft and a mating hub. A circumferential groove around a change in diameter is a different feature (e.g., relief/undercut), not a keyway.

Given Data / Assumptions:

• Keys fit into keyways to transmit torque.
• Keyways run longitudinally (axially) along the shaft surface.
• Circumferential grooves serve other purposes (stress relief, snap-ring seats).

Concept / Approach:
Map function to geometry. Torque transmission requires an axial slot aligning with the hub keyseat. A groove around the diameter does not locate a rectangular key and does not serve the locking function of a keyway.

Step-by-Step Solution:

Verification / Alternative check:
Standards for keys/keyways specify width, depth, and axial position; relief grooves and snap-ring grooves have distinct standardized callouts.

Why Other Options Are Wrong:
References to tapered shafts, Woodruff keys, or fillet reliefs do not convert a circumferential groove into a keyway.

Common Pitfalls:
Confusing undercuts or ring grooves with keyways; misdimensioning orientation (axial vs circumferential).

Final Answer:
Incorrect