shoal shoal /ʃoʊl/

noun

1. A large group of fish  ( school , shoal )
   a large group of fish
    A school of small glittering fish swam by
   a school of small glittering fish swam by
   
   
2. A stretch of shallow water  ( shallow , shoal )
   a stretch of shallow water
   
3. A sandbank in a stretch of water that is visible at low tide  ( shoal )
   a sandbank in a stretch of water that is visible at low tide
    The boat had to navigate carefully to avoid the shoal visible during low tide.
   The boat had to navigate carefully to avoid the shoal visible during low tide.
   
   

verb

1. Become shallow  ( shallow , shoal )
   become shallow
    The lake shallowed over time
   the lake shallowed over time
   
2. Make shallow  ( shallow , shoal )
   make shallow
    The silt shallowed the canal
   The silt shallowed the canal