潜在语义分析（Latent Semantic Analysis），是语义学的一个新的分支。传统的语义学通常研究字、词的含义以及词与词之间的关系，如同义，近义，反义等等。潜在语义分析探讨的是隐藏在字词背后的某种关系，这种关系不是以词典上的定义为基础，而是以字词的使用环境作为最基本的参考。这种思想来自于心理语言学家。他们认为，世界上数以百计的语言都应该有一种共同的简单的机制，使得任何人只要是在某种特定的语言环境下长大都能掌握那种语言。在这种思想的指导下，人们找到了一种简单的数学模型，这种模型的输入是由任何一种语言书写的文献构成的文库，输出是该语言的字、词的一种数学表达（矢量）。字、词之间的关系乃至任何文章片断之间的含义的比较就由这种矢量之间的运算产生。

Latent semantic analysis (LSA) is a technique in natural language processing, in particular distributional semantics, of analyzing relationships between a set of documents and the terms they contain by producing a set of concepts related to the documents and terms. LSA assumes that words that are close in meaning will occur in similar pieces of text. A matrix containing word counts per paragraph (rows represent unique words and columns represent each paragraph) is constructed from a large piece of text and a mathematical technique called singular value decomposition (SVD) is used to reduce the number of rows while preserving the similarity structure among columns. Words are then compared by taking the cosine of the angle between the two vectors (or the dot product between the normalizations of the two vectors) formed by any two rows. Values close to 1 represent very similar words while values close to 0 represent very dissimilar words.