Origins of Mathematical Words: A Comprehensive Dictionary of Latin, Greek, and Arabic Roots

L

191 writes Kyrie eleison for kÚrie ™lšhson, not Kurie eleison. Thus, the word should be spelled kyrtosis. In the theory of probability, the kyrtosis factor is the fourth moment of the standardized random variable; it is usually denoted a4. L lacuna This is a Latin noun with the meaning cavity, hollow, dip. It is used by textual critics to describe a situation where some words have fallen out of a text. The accent is on the middle syllable. lacunary From the Latin adjective lacunarius meaning having empty spaces came the English adjective lacunary, by the dropping of the nominative ending -us and the change of the then final i to the betterlooking y. lambda The letter l of the Greek alphabet is traditionally used for a characteristic value of a matrix. The capital lambda, L, is used as an artsy A by people not encumbered by any knowledge of Greek. lamina This is the Latin word for a plate. The Latin plural, laminae, is, alas, not used in English; instead, it is fine to say laminas. The accent is on the first syllable. large This word is from the Latin largus, -a, -um, which means abundant, copious. There is an interesting passage relating to the law of large numbers in the book Religion and Science by Bertrand Russell (Oxford University Press, 1961, p. 158): It is said (though I have never seen any good experimental evidence) that if you toss a penny a great many times, it will come heads about as often as tails. It is further said, that this is not certain, but only extremely probable. You might toss a penny ten times running, and it might come heads each time. There 192 would be nothing surprising if this happened once in 1,024 repetitions of ten tosses, but when you come to larger numbers, the rarity of a continual run of heads grows much greater. If you tossed a penny 1,000,000,000,000,000,000,000,000,000,000 times, you would be lucky if you got one series of 100 heads running. Such at least is the theory, but life is too short to test it empirically. Actually, the law of large numbers assures us that if you want the probability to be at least 99% that the difference between heads and tails will be at least one million, it is enough to toss the penny 6,400,000,000,000,000 times. The probability of the event mentioned in the penultimate sentence is actually about 40%. The law of large numbers appeared for the first time before the learned world in Chapter IV of the posthumous Ars Conjectandi of Jakob Bernoulli (1713): Suppose we toss a fair coin n times. If X is the number of heads obtained in those n tosses, then, given ε > 0 the probability that ½ – ε 0, then the probability that |X– (n – X)| > M also tends to 1 as n approaches infinity. lateral From the Latin noun latus meaning side, there was formed the adjective lateralis with the meaning on the side. Lateral is therefore the Latin adjective with the nominative case ending -is omitted. Latin square The adjective latinus means belonging to Latium, the region around Rome. See also the entry square. A Latin square is an n n square array, each of the n2 entries of which is chosen from n different symbols in such a way that each symbol appears exactly once in each row and exactly once in each column. latitude From the Latin latus, -a, -um, wide, came the noun latitudo by the addition of the nominal suffix -tudo. From this word proceeded the English noun latitude. latus rectum This is a Latin phrase meaning perpendicular side. The latus rectum of an ellipse, a hyperbola, or a parabola is the chord through a focus perpendicular to the major axis of the ellipse, the 193 transverse axis of the hyperbola, or the axis of the parabola, respectively. The Latin plural, which in this case must be used, is latera recta. English plurals like latus rectums or latuses rectums are comical. lemma This is the Greek word lšmma meaning a peel, husk, skin, or scale that is peeled off, from the verb lšpw, to strip off, to peel. The Greek plural is lšmmata, lemmata, but the English plural lemmas is in this case sufficiently sanctioned by custom so as to...