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Aa Lava Flow

Consider the word aa. It is surely worthy of consideration, as it is one of the first words in most dictionaries — the very first possible word of two letters, in fact. There are only 101 two-letter words in the English language, according to the authoritative source. That’s a small enough number that any person who loves the language, as I do, can easily learn them all, and I aim to. It’s not enough to know that a word exists. I want to know where it came from and what it means. Aa is the place to start.

I’ve known this word since a middle school geology lesson, as a type of particularly rough volcanic rock. My science teacher told us that the name derived from the sound native Hawaiians would make as they ran barefoot across the jagged surface of the rock. Ah! Ah! As a boy I accepted this uncritically, and perhaps it’s a useful mnemonic. However, I now view that folk etymology as incorrect, not to mention vaguely insulting. According to an entry from a Hawaiian dictionary, I’m guessing the geologic meaning may derive from its primary association with burning and fire.


1. nvi. To burn, blaze, glow; fire; staring, as eyes (see ʻaʻā maka). Fig., angry; fury. ʻAʻā koke, combustible, inflammable. Ua ʻaʻā ka puʻu, the throat is on fire [with great thirst]. Ke ʻaʻā maila ka wahine, the woman burns hither [Pele and her volcanic fires approach]. Ua ʻaʻā ʻia au i ke aloha (FS 21), I burn with love. hoʻa.ʻā To kindle, light. Mea hoʻaʻā, fire kindling. (PNP kakaa.)

2. nvs. ʻAʻā lava; stony, abounding with ʻaʻa lava.

3. (Cap.) n. Sirius, a zenith star that passes over Tahiti and Raʻi-ātea, formerly believed used by navigators; one of the brightest stars in the heavens. See Sirius for var. names.

4. n. Young stage of damselfish (ʻāloʻiloʻi). Also ʻā.

It’s also useful to know the four words that can be derived by adding a single letter to aa. There’s baa, which is the sound a sheep makes; aah, an exclamation of amazement; and aas, which I assume night be the plural of aa. And then there’s aal, which is new to me. It’s an evergreen shrub, Morinda tinctoria, commonly known as the Indian mulberry. The root bark of the young plant is used to make red, brown or purple morindone dye.

Thus endeth the lesson.

Photo: Aa Lava Flow by C. Carlstead, licensed under Creative Commons

Published inWords & Numbers


  1. […] that sounds awfully familiar. Aha, that’s because I wrote about the variant spelling aal already. It’s an evergreen shrub, Morinda tinctoria, commonly known as the Indian mulberry. The root […]

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