1590s, earlier nepenthes (1570s), "a drug or magic potion of Egypt mentioned in the 'Odyssey' as capable of banishing grief or trouble from the mind," from Greek nēpenthēs, from nē- "no, not" (from PIE root *ne- "not") + penthos "pain, grief," from PIE root *kwent(h)- "to suffer." The -s is a proper part of the word, but likely was mistaken in English as a plural affix and dropped. In medical use, "a drug having sedative properties" (1680s).
