Definitions
from Wiktionary, Creative Commons Attribution/ShareAlike License
 n. A magma: a set with a total binary operation.
 n. A set with a partial binary operation that is associative and has inverses and identities.
Etymologies
group + oid (Wiktionary)
Examples

Heller's current work focuses on noncommutative geometry and groupoid theory in mathematics which attempts to remove the problem of an initial cosmological singularity at the origin of the universe.

B 268, 253 (1986) that for interacting strings the splitting and joinings define a groupoid structure.

136, 369397 (1991) Wiesbrock constructs a C*algebra which carries all the representations of this groupoid.

(ie. with groupoid like arrows above dimension $n$) related to the classification of TFTs.
Comments
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