The place where two points meet is known as an intersection in math.
The term that describes two coplanar lines that do not intersect is "parallel lines." These lines maintain a constant distance from each other and will never meet, regardless of how far they are extended in either direction.
They meet at right angles
Concave is not a shape, it is the term for when two lines meet facing inwards, rather than outwards (outwards is known as convex)
When two people physically meet, it is often referred to as a "meeting" or "encounter." In more informal contexts, it can also be called a "get-together" or "face-to-face." The specific term may vary depending on the nature of the meeting, such as a "greeting" or "introduction."
The armies of the north are scheduled to meet tomorrow.
No, frontier is any unexplored area which is why space may be the final "frontier".
When two waves meet, their interaction is known as interference.
corner
The place where two points meet is known as an intersection in math.
Potsdam
Interface is where two structures meet. Not to be confused with intersection, where one structure crosses another.
Don't frickin use this website!
node Any number of currents can meet at a node, not just two.
Yorktown, Virginia
Chaldiran
Engaged in that case means to be involved in battle. When two armies meet on a battlefield they are said to have "engaged" each other.