n. (fixed, adj.) ~ The quality of being stable and resisting change.
Documents preserve memory because they fix information on a stable medium. The information may fade with time, or it may be may erased and overwritten, but barring external action the information remains unchanged over time.
†(InterPARES2, p. 3) The special challenges for making and keeping reliable records and preserving authentic records, the most salient characteristic of which is the lack of a stable form and content (that is, of fixity), as is the case with experiential, interactive and dynamic records.
†(USC, 17 USC 101) Copyright · A work is 'fixed' in a tangible medium of expression when its embodiment in a copy or phonorecord, by or under the authority of the author, is sufficiently permanent or stable to permit it to be perceived, reproduced, or otherwise communicated for a period of more than transitory duration. A work consisting of sounds, images, or both, that are being transmitted, is 'fixed' for purposes of this title if a fixation of the work is being made simultaneously with its transmission.