5-wide

From Openwaterpedia

noun - 5-wide (Five-wide) is a formation of five open water swimmers or triathletes swimming side-by-side during a race or training session.

There was a 5-wide coming around the last turn buoy.

Its equivalents (3-wide, 4-wide, 6-wide, etc.) are used when there are more individuals swimming side-by-side.

Origin

Usage dating to circa 2001 from Steven Munatones in Huntington Beach, California as adopted from the modern-day application of a NASCAR term.

4-wide example

with Darren Miller, Jamie Patrick, Jen Schumacher and Oliver Wilkinson across the Strait of Gibraltar