We don't have synonyms for groundline yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are groundling, grounding and ground line.
(n) :
(fishing) A weighted fishing line that lies along the floor of the body of water in which the user is fishing.
(n) :
In equestrian show jumping, a marker such as a row of flowers which signifies the point from which a horse should begin a jump over an obstacle.
(n) :
(art) A line drawn to signify the surface of the ground, especially in architectural blueprints and in drawings by children which lack dimension.
(n) :
(fishing) A weighted fishing line that lies along the floor of the body of water in which the user is fishing.
(n) :
In equestrian show jumping, a marker such as a row of flowers which signifies the point from which a horse should begin a jump over an obstacle.
(n) :
(art) A line drawn to signify the surface of the ground, especially in architectural blueprints and in drawings by children which lack dimension.