The most common and most likely answer to this crossword clue is the 10 letter word PROPAGATED
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More clues leading to the result PROPAGATED
Buddy explains!

The straight part
We know that "Spread" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case spread = propagated.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 PROPAGATED mean?
PROPAGATED verb- (of animals or plants) To cause to continue or multiply by generation, or successive production
- To cause to spread to extend; to impel or continue forward in space
- To spread from person to person; to extend the knowledge of; to originate and spread; to carry from place to place; to disseminate
- To multiply; to increase.
- To generate; to produce.
- To produce young; to be produced or multiplied by generation, or by new shoots or plants
- To take effect on all relevant devices in a network.
- To cause to take effect on all relevant devices in a network.