GEOMETRY. BASIC TERMS

• Endpoint (punto)                    

−      A point is the place where two lines intersect.

−      In geometry, a point has no dimension

−      We represent a point with a dot.

−      We identify this point with a CAPITAL letter.

• Line (línea)

−        A line is made up of infinite points.

−        It has not endpoints and continues endlessly on a plane. 

−        These lines are named with small letters such r ,s, t...

• Ray (semirrecta)

−      A ray is a "straight" line that begins at a certain point and extends forever in one direction.

−      The point where the ray begins is known as its endpoint.

• Line segment (segmento)

−        A line segment is a portion of a "straight" line.

−        A line segment does not extend forever, but has two endpoints.

−      The point halfway between the endpoints of a line segment is called the midpoint.  A midpoint divides a line segment into two equal segments.

• Intersection

−        The term intersect is used when lines, ray lines or segments share a common point.

−        The point they share is called the point of intersection.

 

You  can find here a funny introductory video about the origins and basis of Geometry.

 And here you can find a video explaining the differences between line, line segment and ray.