Short answer
Oxford is a cotton basket weave cloth of about —, at its best in all year (shirts). A heavier, textured cotton that reads relaxed and survives casual washing.
At a glance
Choosing Oxford at your fitting
Tell the tailor your cities and your calendar — Oxford earns its place when the answer matches all year (shirts) wear. The shortlist you receive will pair it with one or two alternatives, and the choice is always yours.
Cloth notes are guidance, not inventory: availability varies by season. What is reserved for you is confirmed in your written quotation.