The most common and most likely answer to this crossword clue is the 6 letter word RHYTON
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More clues leading to the result RHYTON
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The straight part
We know that "Old drinking container" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old drinking container = rhyton.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 RHYTON mean?
RHYTON noun- A container from which fluids are intended to be drunk, having one handle and usually a base in the form of a head.
- A Thracian drinking horn.