Cum hoc
Etymology
Short for the Latin "cum hoc ergo propter hoc," "with this, therefore because of this." It is the correlation-based twin of the post hoc fallacy, which relies on sequence instead. Both ignore that a third factor, or pure chance, may explain the pattern.
noun phrase · /koom-HOK/
Assuming that because two things occur together, one must cause the other.
What it names
Captures the "correlation is not causation" warning in a single handle for everyday use.
Example
Ice-cream sales and drownings rise together, but concluding cones cause drowning is cum hoc — summer heat drives both.
Related idea
The Texas sharpshooter compounds it by first cherry-picking which correlations to notice at all.