To help break down this concept—often highlighted by strategists like Charlie McElligott in their market notes

=> What is a swaption ?

A swaption (short for swap option) is an option on an interest-rate swap. It grants the holder the right—but not the obligation—to enter into a swap agreement on a future date at a fixed rate agreed upon today (the strike $K$).

Three key temporal milestones matter:
Today — The buyer pays a premium to the seller to acquire the option.
Expiry — The date when the buyer chooses to exercise the option or walk away.
Tenor — The duration of the underlying swap once the option is exercised.

=> How swaptions are quoted ?
This structure is why swaptions are universally quoted as Expiry × Tenor:
A 1y1y (1-year by 1-year) is a 1-year option on a 1-year swap.
A 3y10y (3-year by 10-year) is a 3-year option on a 10-year swap.