What is the word for the point where two lines come together, if that point is at the bottom of the whole?
For example, in a cone (so this isn't exclusively lines), pointed down, what would you call the point?
Vertex is a possibility as it means
• each angular point of a polygon, polyhedron, or other figure.
• a meeting point of two lines that form an angle.
However, it also means
• the highest point; the top or apex
which is in fact the opposite of the meaning I seek, and could lead to confusion.
Nadir, as the lowest point, could work but it makes no reference to anything coming together and, I believe, only used figuratively except for in reference to astronomy.
Use in a sentence:
• We need to put a gutter at the ---- of the (inverted) roof, where the two sides slope down to each other.
• The font-designer recommended that his student make the capital M's ---- sharper.
(Note: I choose M rather than V because the lower angle of the M is not in fact the lowest part of the M—it is not the base or the bottom. It's primary identity is as a vertex, except that vertex also indicates apex.)
Edit and possible answer:
Juncture, a place where things join
which carries no meaning of top.
All definitions from NOAD.