segment
is the part of a line consisting of two endpoints and all points between them.
ray
is the end part of a line consisting of one endpoint and all points between them
opposite rays
are 2 collinear rays with the same endpoint. Them form a line
skew lines
noncoplanar, not parallel and do not intersect
parallel lines
are coplanar lines that do not intersect
parallel planes
are planes that do not intersect