We describe how chiral matter charged under SU(N) and SO(2N) gauge groups
arises from codimension seven singularities in compactifications of M-theory on
manifolds with G(2) holonomy. The geometry of these spaces is that of a cone
over a six-dimensional Einstein space which can be constructed by (multiple)
unfolding of hyper-Kahler quotient spaces. In type IIA the corresponding
picture is given by stacks of intersecting D6-branes and chiral matter arises
from open strings stretching between them. Usually one obtains (bi)fundamental
representations but by including orientifold six-planes in the type IIA picture
we find more exotic representations like the anti-symmetric, which is important
for the study of SU(5) grand unification, and trifundamental representations.
We also exhibit many cases where the G(2) metrics can be described explicitly,
although in general the metrics on the spaces constructed via unfolding are not
known.
