An allowance for work that is not sufficiently defined or measured when the price is prepared.
Why it matters
It signals that the final amount may change once the scope is designed, instructed or measured.
Example in practice
The quote includes a provisional sum for drainage alterations pending a survey and final layout.
Use the term carefully
State the work covered, the information still missing and how the final amount will be agreed under the project terms.
Compare related terms
Use the price-review checklist to keep the client wording and approved basis consistent.