be on to
Proposed by a contributor, not yet supported by evidence.
Also seen as: be onto
Meaning · English
discover or realize the truth about something
Nghĩa · Tiếng Việt
phát hiện hoặc nhận ra sự thật về một điều gì đó
Machine-translated — suggest a fix
Literally: be on top of
Where it’s used:
Used
Widespread English
Examples
The police are on to the suspect's plan
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-30; pending editor spot-check.
Common questions
What does “be on to” mean?
discover or realize the truth about something Literally: be on top of
Is “be on to” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.