Definition
A transaction fee is a charge associated with submitting, executing, settling, transferring, or recording a financial or blockchain transaction for the user.
In market context
Fees may be fixed, percentage based, embedded in a spread, charged by a venue, or paid to a network independently of the platform. Their effect grows with turnover and small transaction size, and some failed blockchain transactions still incur network cost. Users should review estimated and final charges, external intermediary costs, currency conversion, and whether a fee is deducted from cash, proceeds, or transferred quantity.
Source
Use the primary source for fuller regulatory or market context.
