should I be worried?

[alexeberlin]

I've used a couple of local tailors previously, and contacted another following a recommendation from an old friend. I enquired about a grey nailhead worsted two-piece, to have the tailor ( and it was the tailor I spoke to) tell me that he'd never heard of nailhead worsted, did I mean pinhead?
I realise that I'm showcasing my ignorance once again but are there two different names for the same fabric? thank you

[Concordia]

Not identical, but close enough that not everyone cares about or can articulate the difference.

[hectorm]

A tailor that never heard of a nailhead pattern? Mmmhhhh......
Maybe he was trying to prove something to you.
Was this conversation taking place in English? If those terms were translated then there could be some misunderstanding.
Nailhead, pinhead (and I would add, birdseye) -as Concordia said- are similar but with differences.
Nailhead and pinhead are very small square patterns in which the center of the square are occupied by lighter round "nail" or "pin" heads against a darker background. Birdseye is a more continuous diagonal or diamond pattern with less background and more "eyes".
Despite the similarities, a tailor should not mistake one for the other. Actually these differences in patterns make for differences in the formality and shade (how the light interacts) of the suit. Pinheads are more formal and look better in darker charcoal suits; birdeyes IMO are a bit more informal and look better in medium grey suits.