A sum carried to manage identified uncertainty or potential change that is not priced as defined work.
Why it matters
Contingency is not margin. Keeping it visible helps the reviewer understand how much risk is being carried in the price.
Example in practice
The internal estimate carries contingency for a known access risk while the quote states the assumption used.
Use the term carefully
State the scope, amount, adjustment method or contract meaning whenever this term could change who carries cost or risk.