arce fu'ivla

x1 is a maple (Acer) of species/variety x2

The genus from the Linnaean name is "Acer".

On gloss:

krogarna in sense "shape"
k1=g1 is bow/arc supporting/restraining g2, of material g3.

In definition:

x1 is lightning/electrical arc/thunderbolt striking at/extending to x2 from x3.
x1 is the conceptualized/ideal/abstract shape of a biconvex lens formed by/manifested from the intersection x2 (parameters) of two-dimensional circular disks immersed (embedded) in geometry/defined by metric x3; x1 is the convex-only region bounded by intersecting circular arcs given by x2
x1 (shape/form) is (idealized as) a quadrilateral/two-dimensional closed shape bounded by exactly four distinct non-colinear line-segments (or circular arcs), with vertices x2 (ordered cyclical list) and with additional properties x3.

In notes:

x1 arches/curves over/around x2 and is made of x3; x1 is an arch over/around x2 of material x3.