Origins
The word 'amber' has a tangled history involving two entirely different substances, two different source languages, and a semantic swap that left the word attached to the wrong material.
The English word comes from Middle English 'ambre,' from Old French 'ambre,' from Medieval Latin 'ambra,' from Arabic 'ʿanbar' (عنبر). In Arabic, 'ʿanbar' meant ambergris — the waxy, grey, fragrant substance produced in the digestive systems of sperm whales, prized for centuries as a fixative in perfumery. The Arabic word may derive from Middle Persian.
The fossilized tree resin that we now call amber was a different substance with a different name in many traditions. The Greeks called it 'ēlektron' (ἤλεκτρον), possibly meaning 'beaming sun' — the resin's warm golden color suggested captured sunlight. The Baltic peoples, who lived near the world's richest amber deposits along the coast of what is now Lithuania, Latvia, and Poland, had their own indigenous names.
Development
Confusion between the two substances arose in medieval European trade. Both were exotic luxury goods — translucent, warm-toned, and valuable. French distinguished them as 'ambre gris' (grey amber = ambergris) and 'ambre jaune' (yellow amber = the resin). In English, however, the unmodified word 'amber' gradually shifted to refer primarily to the resin, while the whale product retained the full form 'ambergris' (from French 'ambre gris').
The scientific legacy of the Greek name for amber is immense. In 1600, the English physician William Gilbert published 'De Magnete,' in which he coined the Latin term 'electricus' from Greek 'ēlektron' to describe the attractive force produced when amber is rubbed. This gave rise to 'electricity,' 'electron,' 'electrode,' 'electronics,' and the entire vocabulary of electrical science. The connection is not arbitrary: amber's electrostatic properties were well known to the ancients. Thales of Miletus (6th century BCE) observed that rubbed amber attracted feathers and straw, making amber arguably the first material in which electrical phenomena were systematically noticed.
Amber has also been scientifically invaluable for its ability to preserve biological specimens. Insects, spiders, plant material, and even small vertebrates trapped in amber resin millions of years ago are preserved with extraordinary fidelity. The oldest amber with inclusions dates to approximately 230 million years ago (Triassic period). Baltic amber, the most commercially important variety, is typically 35–50 million years old.
Greek Origins
The dual etymology — Arabic 'ʿanbar' for the English word, Greek 'ēlektron' for the science — is one of the more remarkable cases in English of two entirely different linguistic traditions converging on the same physical object.