Endurance (late 15th century) comes from the Middle French endurance.  It's derived from the Latin indurance ("to make hard"), via the prefix in- ("in"), with durus ("hard"), and the suffix -ance, (a Latin-based suffix, via French, denoting "a state, quality, or process").  It roots to the Proto-Indo-European (PIE) root *deru- ("be firm, solid, steadfast"), reflecting the capacity to withstand strain or continue existing.  The core PIE root *deru- is shared with other words indicating firmness, such as durable, dour, druid, and true. It is also related to terms that mean "to hold out," such as dure (to last) and obdurate (hardened).   

According to the Oxford English Dictionary (OED), the earliest known use of the noun endurance is from before 1513.  The OED cites the work of chronicler Robert Fabyan (1470-1513, was given the date of a 1513 to indicate it was published posthumously) as the first known use.  Historical meaning are as follows: Original 15th-century Meaning: Initially, it referred to "continued existence in time", which is now an obsolete sense.  16th-century sense: Associated with "imprisonment" or "restraint" (1510s), highlighting the notion of being stuck or confined.  17th-century usage: Evolved to mean the ability to suffer or bear hardship (1660s).  Contextual Evolution: The meaning "ability to bear suffering" is recorded later, from the 1660s.  Related Forms: The verb endure was used earlier, dating back to 1340 and was found in the writings of Richard Rolle of Hampole, a Middle English hermit, mystic, and religious author. 

Just the facts:

ENDURANCE Definition & Meaning - Merriam-Webster

ENDURANCE Synonyms: 36 Similar and Opposite Words | Merriam-Webster Thesaurus

Endurance is what I hope I have from now until June if none of the jobs I've applied for come through.