Just wondering what "MERMA" means on the Los Angeles TAC chart:
MERMA is an aviation waypoint
Waypoints used in aviation are given five-letter names. These names are meant to be pronounceable or have a mnemonic value, so that they may easily be conveyed by voice.
According to this page back before the FAA decided all waypoints must have 5 character names, this waypoint - being out in the ocean - was called "Mermaid" and after renaming this became simply MERMA.
It's an intersection, as described in the FAA Aeronautical Chart User's Guide (VFR Sectional & TAC section):
Named intersections used as reporting points. Arrows are directed toward facilities which establish intersection.
If you follow the arrows that make up the MERMA intersection symbol, it's defined by the intersection of radial 246 from the LAX VORTAC and and radial 148 from the FIM VORTAC. MERMA is used in some instrument procedures, like the OCEAN TWO arrival into KLAX.