coincidentally.

By chance, without a planned or necessary connection.

Use it for

Words that belong together

• coincidentally similar
• coincidentally occurred
• not coincidentally

On the page

The two surveys began on the same date coincidentally, not through coordination.

Usage notes

Primary category: analysis / argumentation / evidence. Forms: invariable adverb. Writing functions: causation, qualification, comparison. Commonness: moderately common. Established English; no emotional intensity assigned.