What does the three horizontal lines mean?
A symbol with three horizontal line segments ( ) resembling the equals sign is used to denote both equality by definition (e.g., means is defined to be equal to ) and congruence (e.g., means 13 divided by 12 leaves a remainder of 1–a fact known to all readers of analog clocks).
What do triple lines mean?
Two lines means something is equal to something. Example: x=5, y=7. Three lines means that something is identical or similar to something, but not necessarily equal to that something. Example: x (triple bar) 5, y (triple bar) 7.