Is there oil without olives?

Question

Is the Latin word oleum ("oil") related to oliva ("olive")? If yes, how?

The two words look similar, but oleum does not look like a regular derivative to me. Many dictionaries mention that oleum means "oil" or "olive oil", but that could be just because olive oil was the most common oil in antiquity. Another option that comes to mind is that oleum comes from olere due to its smell.

Lewis and Short does not discuss etymology within Latin, but links to a Greek word. In Greek the similarity is more obvious (ἔλαιον=oleum and ἔλαιος=oliva), but it is not clear if oleum and oliva were borrowed from Greek separately, if oleum was derived from oliva in Latin, or if something else happened.

Answer 1

The current communis opinio is both Latin words oleum and oliva were borrowed from Greek, which, in its turn, are of Pre-Greek origin (e.g. Beekes 2009/2016, Ernout & Meillet 2001); cf. Miller 2014 "there are cultural and phonological reasons for thinking Latin borrowed it from Greek" (p. 31).

Miller 2014 writes that

"Since Attic-Ionic lost /w/ prehistorically, Greek words borrowed into Latin with v /w/ are either from a West Greek (Doric) dialect, or possibly early enough to have been Mycenaean loans" (p.31).

Latin oleum < *olēwom < *eleiwom < Gk. *élaiwon (Miller 2014), cf. ἔλαιον

Latin oliva < Gk. *elaíwā (Beekes 2009/2016), cf. ἐλαία

All of the sound changes above are well-known and described in any historical Latin grammar worth reading, e.g. Weiss 2009/2011 (the first book I grabbed from my bookshelves).

• *e > o/_ɫ (p. 139);
• ai > ei > e (> i) (a-weakening, Weiss tells us, precedes monophthongization, p. 120);
• *ei > *ẹ̄ > e (p. 143) etc.

As for a possible Etruscan intermediary hypothesis suggested by TKR (was it borrowed directly from Greek or via Etruscan?), this is highly speculative. As Clackson and Horrocks 2007/2011 write,

"All languages of central Italy participate in borrowing words for material artefacts from Greek. Often we may be unable to tell whether a word came directly from Greek or via the medium of another language: Greek *kulίkʰna 'cup' borrowed as Latin culigna, Etruscan culicna, Oscan culchina/culcfna" (p. 46; emphasis mine — Alex B.).

For more information we will need to look it up in De Simone 1968–1970 and Watmough 1997 — and I will. I encourage you to read these books too!