Can the word check be a synonym for plaid?

No, "check" is not a synonym for "plaid." While both patterns involve squares, they are distinct:

* Check: A pattern of alternating squares of two colors, typically in a simple, even arrangement.

* Plaid: A pattern of colorful, often interlocking, stripes or bands that create squares or rectangles.

Here's a simple way to think about it:

* Check is like a checkerboard.

* Plaid is like a tartan kilt.

So, while both are patterns, they are different in appearance and design.