of particular words. Such hypotheses are tested against the general knowledge of semantic shifts. For example, the assumption of a particular change of meaning may be substantiated by showing that the same type of change has occurred in other languages as well. Types of word origins Etymological theory recognizes that words originate through a limited number of basic mechanisms, the most important of which are language change, borrowing (i.e., the adoption of "loanwords" from other languages); word formation such as derivation and compounding; and onomatopoeia and sound symbolism (i.e., the creation of imitative words such as "click" or "grunt"). While the origin of newly emerged words is often more or less transparent, it tends to become obscured through time due to sound change or semantic change. Due to sound change, it is not readily obvious that the English word set is related to the word sit (the former is originally a causative formation of the latter). It is even less obvious that bless is related to blood (the former was originally a derivative with the meaning "to mark with blood"). Semantic change may also occur. For example, the English word bead originally meant "prayer". It acquired its modern meaning through the practice of counting the recitation of prayers by using beads. History The search for meaningful origins for familiar or strange words is far older than the modern understanding of linguistic evolution and the relationships of languages, which began no earlier than the 18th century. From Antiquity through the 17th century, from to Pindar to Sir Thomas Browne, etymology had been a form of witty wordplay, in which the supposed origins of words were creatively imagined to satisfy contemporary requirements; for example, the Greek poet Pindar (born in approximately 522 BCE) employed inventive etymologies to flatter his patrons. Plutarch employed etymologies insecurely based on fancied resemblances in sounds. Isidore of Seville's Etymologiae was an encyclopedic tracing of "first things" that remained uncritically in use in Europe until the sixteenth century. Etymologicum genuinum is a grammatical encyclopedia edited at Constantinople in the ninth century, one of several similar Byzantine works. The thirteenth-century Legenda Aurea, as written by Jacobus de Varagine, begins each vita of a saint with a fanciful excursus in the form of an etymology. Ancient Sanskrit The Sanskrit linguists and grammarians of ancient India were the first to make a comprehensive analysis of linguistics and etymology. The study of