Major on Third?

Ok, just a quick one, its beein bugging me for a while, but what does major on 3rd mean, in terms of memory??
Ive seen it on loads of brands, on different sites, and heard it said before but i have no clue to what it means. Does someone care to share with me what it means?

cheers
Kieron

I've never heard that. Could you post an example or link?

Major brand memory chips on a 3rd party pc board. Funny Brit-speak for generic