The most common and most likely answer to this crossword clue is the 4 letter word DUAL
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More clues leading to the result DUAL
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The straight part
We know that "Double" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case double = dual.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DUAL mean?
DUAL noun- Of an item that is one of a pair, the other item in the pair.
- Of a regular polyhedron with V vertices and F faces, the regular polyhedron having F vertices and V faces.
- (grammar) dual number The grammatical number of a noun marking two of something (as in singular, dual, plural), sometimes referring to two of anything (a couple of, exactly two of), or a chirality-marked pair (as in left and right, as with gloves or shoes) or in some languages as a discourse marker, "between you and me". A few languages display trial number.
- Of a vector in an inner product space, the linear functional corresponding to taking the inner product with that vector. The set of all duals is a vector space called the dual space.
- To convert from single to dual; specifically, to convert a single-carriageway road to a dual carriageway.
- Exhibiting duality; characterized by having two (usually equivalent) components.
- Acting as a counterpart.
- Double.
- (grammar) Pertaining to grammatical number (as in singular and plural), referring to two of something, such as a pair of shoes, in the context of the singular, plural and, in some languages, trial grammatical number.
- Being the space of all linear functionals of (some other space).
- Being the dual of some other category; containing the same objects but with source and target reversed for all morphisms.