poison

Distinctions

eres (ארס)

Not in Tanach or Mishnah; it appears in Hebrew passages of the Bavli and a few times in the Yerushalmi, there usually with a yod after the aleph, so likely iras. The Gemara's usage fixes the sense. Avodah Zarah 30b: three kinds of eres, a young snake's which sinks in a liquid, an old snake's which floats, a middle-aged one's between (Sukkah 50a, Bava Kamma 115b). Avodah Zarah 31b: all sheratzim have eres, but only a snake's kills. Sanhedrin 78a and Bava Kamma 23b ask whether a snake releases venom only when angered. So eres is venom, usually a snake's; this is what Bigsan and Seresh meant for the king's cup (Megillah 13b).

Rashi (to Shabbos 62b) derives eres by metathesis from ka'as, anger, since a snake emits venom only when angered. Rabbeinu Efrayim reverses it: ka'as comes from eres, since anger puts poison in a man's heart. The Gemara already uses the connection, expounding the name of Kalev's daughter Achsah (Yehoshua 15:16-17, Shoftim 1:12-13, Divrei HaYamim I 2:49) as one whose beauty made every man who saw her angry at his wife, playing ע-כ-ס against כ-ע-ס. Rabbi Menachem Azariah of Fano reads her name as marking her a gilgul of Tzipporah, who saved Moshe from death by nachash through the milah (Shemos 4:24-26).

sam hamaves (סם המות)

Literally the potion of death. Not in Tanach; once in Mishnah, where an animal that swallowed sam hamaves or was bitten by a snake is no tereifah but is still forbidden as dangerous (Chullin 3:5). The two are listed separately there, which shows sam hamaves is not venom. In the Gemara: whether a radish is sam hachaim or sam hamaves (Eruvin 56a), Torah learned without proper intent (Taanis 7a), a mother's oath on her child's life (Gittin 35a), and liability for killing another's animal by feeding it (Bava Kamma 47b, 56a).

Because sin and samech interchange, Midrash Sechel Tov, Midrash Aggadah and Daas Zekeinim read vayusam lefanav le'echol (Bereishis 24:33; the article prints 23:33) as a hint that Besuel tried to poison Eliezer; a commentary ascribed to Rashi on Divrei HaYamim II 22:10 has Asaliah killing this way too. Pappenheim takes ס-מ / ש-מ as putting a thing in its place, and derives samim, the ketores ingredients (Shemos 30:7, 30:34, 40:27; Vayikra 16:12), from their being kept in designated places. So sam hamaves is the general word, covering any lethal preparation and naming none in particular.

rosh (ראש / רוש), chamat (חמת)

Rosh: Devarim 29:17, Iyov 20:16, Eichah 3:19 and elsewhere. Targum and Rashi (to Yirmiyahu 8:14) take it as poison drawn from a snake's rosh, its head, so essentially venom. It is normally spelled with an aleph, like the word for head, once with a vav (Devarim 32:32). Others take it as a plant extract, Rabbi Yehuda Feliks identifying it with poppy or conium, and Pappenheim traces it to ר-ש, head, for that plant's round top. Chamat (Devarim 32:33, Tehillim 58:5) is venom named for what a snake emits when its cheimah is aroused, the same anger motif as Rashi's eres, here in the word itself.

ra'al (רעל) and tarelah (תרעלה)

Nachum 2:4, Zechariah 12:2; tarelah in Tehillim 60:5, Yeshayahu 51:17, 51:22. Commonly rendered poison, but Rashi (to Yeshayahu 51:17 and Nachum 2:4) says it is a draught that leaves a man weak and unable to move, as though bound. A near word re'alah (Yeshayahu 3:19) is an ornament one wraps oneself in. Radak (to Yeshayahu 51:17 and in Sefer HaShorashim) cites the poison reading but also defines it as shaking or reeling, possibly from ro'ed.

eches (עכס)

A separate dispute, since Rashi reads it as venom. Yeshayahu 3:16 has uvragleihem te'akasnah as a hapax verb; 3:18 has ha'achasim as an ornament, which Rashi and Ibn Ezra explain as special shoes. The Gemara (Shabbos 62b, Yoma 9b): the Bnos Tzion put perfume in their shoes and kicked their feet at the young men in Yerushalayim's markets, infecting them with the yetzer hara, which works like eres. Hence Rashi (to Yeshayahu 3:16) glosses eches as snake venom and the verb as poisoning them to sin; the Vilna Gaon joins the two senses by taking eches as shoes cased in snakeskin. Ibn Ezra and Radak dissent, tying the verb to the noun: the women drew attention by the noise of their shoes, which Radak says chimed like bells. At Mishlei 7:22 Rashi again reads venom, while Rabbi Yeshayah of Trani takes it as a prisoner's ball and chain, akin to the shoe sense (so too Ibn Ezra there and Radak in Sefer HaShorashim), a sin bound to a man and resurfacing on the Day of Judgment (Sotah 3b). The Midrash renders efeh as echis, viper (Mechilta to Shemos 15:22).

la'anah (לענה)

Rabbi Shlomo of Urbino (Ohel Moed) counts la'anah a synonym of rosh, chamat and ra'al, all poison. This is his own novelty: Rashi and Radak call la'anah extremely bitter but not deadly. Default to wormwood.

Rendering guidance

• Eres: "venom." Never "poison" in a sugya where a snake is in view, since Avodah Zarah 31b turns on which creatures' eres is lethal.
• Sam hamaves: "deadly poison," or "a deadly drug" where the substance is fed or administered. Chullin 3:5 lists it beside a snakebite, so rendering it "venom" makes the Mishnah repeat itself.
• Rosh in a pasuk: "poison," with the rosh/head wordplay noted where Rashi's derivation is cited; paired with la'anah (Devarim 29:17), "poison and wormwood," which keeps Rashi and Radak against Rabbi Shlomo of Urbino.
• Chamat taninim (Devarim 32:33): "the venom of serpents," not "poison."
• Ra'al / tarelah: "a reeling draught" or "cup of staggering" following Rashi, "poison" only if the reader is told which reading is taken.
• Trap: English "poison" will take eres, sam hamaves, rosh, chamat and ra'al without protest, and "venom" will take eres, rosh and chamat. When two appear in one passage, force the split: venom for what a snake emits, poison for what a man administers.
• Eches (Yeshayahu 3:16): pick a side and say so. "They poison with their feet" is Rashi; "they tinkle with their feet" is Ibn Ezra and Radak.

Sources

Rabbi Reuven Chaim Klein, "Pick Your Poison," What's in a Word?, Ohr Somayach, 2 Adar Beis 5782 (2022-03-05): raw text in sources/whats-in-a-word/raw/9603-pick-your-poison.md. Primary loci: Bereishis 24:33 (article: 23:33); Shemos 4:24-26, 15:22, 30:7, 30:34, 40:27; Vayikra 16:12; Devarim 29:17, 32:32, 32:33; Yehoshua 15:16-17; Shoftim 1:12-13; Yeshayahu 3:16, 3:18, 3:19, 51:17, 51:22; Yirmiyahu 8:14; Nachum 2:4; Zechariah 12:2; Tehillim 58:5, 60:5; Mishlei 7:22; Iyov 20:16; Eichah 3:19; Divrei HaYamim I 2:49, II 2:3, 13:11, 22:10; Esther 2:21 (Targum Sheini); Megillah 13b; Shabbos 62b; Yoma 9b; Eruvin 56a; Taanis 7a; Gittin 35a; Sotah 3b; Avodah Zarah 30b, 31b; Sukkah 50a; Sanhedrin 78a; Bava Kamma 23b, 47b, 56a, 115b; Chullin 3:5. The Latin virus and Greek etymologies are omitted per house rule 9.