"pertaining to a node or nodes," 1811, from node + -al (1). Nodical "of or pertaining to the nodes" is by 1839. Related: Nodality.
Entries linking to nodal
node n.
early 15c., "a knot or lump," from Latin nodus "knot" (from PIE root *ned- "to bind, tie"). Originally borrowed c. 1400 in Latin form, meaning "lump in the flesh." Meaning "point of intersection" (originally in astronomy, of planetary orbits with the ecliptic) is recorded from 1660s.
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).