Quote Originally Posted by hamishspence View Post
While wikipedia isn't always accurate, it does mention small hand-and-a-half swords, which could be used one or two handed- and it was only quite late, that ones with a grip big enough to easily fit two hands on, appeared:

http://en.wikipedia.org/wiki/Longsword

Compared to those small ones, a claymore probably does qualify as a small greatsword, rather than a large bastard sword.
A lot depends on the size of the wielder as well. Weapon nomenclature is by no means a precise science, and a "two-handed sword" could have a blade length of anywhere from around 36"-60" and a weight of 5-8 lbs. More usually they would be on the shorter and lighter end of the scale, though. The word "claymore" is used most frequently to describe two types of Scottish sword from the very late medieval to early modern period. As noted, however, it translates to "big sword" or some such thing and so was probably initially used to describe a sword larger than was normal.