To customize the word "Record" in the built-in navigation area in the bottom left of a bound form, set the form's Navigation Caption property.
Set Navigation Property
Note that if you want to include the colon character (":") you must include it in the Navigation Caption text, as shown in my example screenshots above.
Perhaps I'm just late to the party, but I've been developing Microsoft Access applications for almost 17 years, and I only recently learned about this feature. Every Access application I've ever written uses the default "Record:" caption in the navigation area. I'd say that's about to change.
Sometimes old dogs can learn new tricks.