Origins
Among common English words for meals, 'lunch' is the most etymologically uncertain. While 'breakfast', 'dinner', and 'supper' all trace to clearly documented sources, the origins of 'lunch' and its longer form 'luncheon' remain the subject of scholarly debate.
The first documented appearances of 'luncheon' date to the 1590s, where it seems to refer to a substantial piece or slice of food rather than a formal meal. The word appears in this sense in several late Elizabethan and Jacobean texts. From 'a lump or slice of food' the word shifted to describe the occasion of eating such food between breakfast and dinner — a light midday refreshment.
One theory, advanced by several etymologists, connects 'luncheon' to Spanish lonja, meaning 'a slice of ham'. Spanish influence on English increased significantly during the 16th century through trade and political contact, and a number of Spanish food terms entered the language in this period. A lonja of ham would have been a familiar sight in markets and taverns, and the word could have been borrowed and adapted. However, the phonological path from lonja to luncheon is not entirely clear, and this etymology remains contested.
Word Formation
A second theory links the word to an English dialectal form 'lunch', recorded in some regional speech to mean a thick piece or hunk of something — bread, cheese, or meat. This dialectal 'lunch' may be related to 'lump' or to Spanish 'lonja' via early borrowing. The dialectal form would then have been formalised and extended by the addition of the suffix '-eon' (as in 'nuncheon', 'puncheon'), yielding 'luncheon'.
The 'nuncheon' theory connects 'lunch' to a completely different source: Middle English nonchenche or nuncheon, meaning a light drink or snack taken at midday or mid-afternoon, from Old English non (the ninth hour, i.e., 3 PM by the Roman system of counting) and scenc (a cup, a serving of drink). Nuncheon became 'noonshine' and then, through various alterations, may have contributed to 'luncheon'. However, most etymologists consider this a less direct path.
The shortened form 'lunch' — dropping the '-eon' — appears in print around 1829, and it rapidly became the preferred everyday term, with 'luncheon' surviving as a more formal or ceremonial word. The pattern of shortening is common in English: 'bus' from 'omnibus', 'gym' from 'gymnasium', 'flu' from 'influenza'.
Later History
Interestingly, the social history of 'lunch' as a concept is as complex as its etymology. For much of English history, the main meals were breakfast, dinner (midday), and supper (evening). As working patterns changed with industrialisation and the middle and upper classes began taking their main meal later in the evening, a new midday refuelling stop became necessary — this was the origin of lunch as a distinct, named meal. The word and the social institution co-evolved in the early 19th century.
The compound 'lunchbox' is first recorded in 1877, and 'lunch break' became a standard term in the industrial workplace vocabulary of the late 19th and early 20th centuries. 'Business lunch' emerged as a distinct category in the 20th century, when the midday meal became a site of commerce and negotiation as much as sustenance.