Untangling "knot"

Today's Lindiga vocabulary exercise is the word "knot". The first thing
I think of is a rope or string that's been tied up (either to attach two
ends together, or to attach the rope or string to something). The
Lindiga word is "wyrne" ["wu\rn@]

There's also a "knot" in a piece of wood, a place where a branch was
attached. This is a more general kind of attachment, which could be
translated by making a word for "joint": rsieng ["s`i@N].

But there are two other meanings that present some difficulty. One is a
unit of speed, "nautical miles per hour". I'm not even sure if Lindiga
would have a single word for a unit of speed. If it did, it'd probably
be "meters per second", and a knot is about half a meter per second
(1,852 meters in 3,600 seconds).

The other one is the bird, _Calidris canutus_, a kind of sandpiper.
(There's also a related bird, _Calidris tenuirostris_, the "Great
Knot"). As far as I'm concerned, one kind of sandpiper is pretty much
like another, and I don't think I need specific words for each kind of
sandpiper. But it'd probably be good to have a word for sandpipers in
general (possibly including related shorebirds): aratl ["araK].