The terminology of algebraic geometry changed drastically during the twentieth century, with the introduction of the general methods, initiated by David Hilbert and the Italian school of algebraic geometry in the beginning of the century, and later formalized by André Weil, Jean-Pierre Serre and Alexander Grothendieck.
Much of the classical terminology, mainly based on case study, was simply abandoned, with the result that books and papers written before this time can be hard to read.
Other books defining some of the classical terminology include Baker (1922a, 1922b, 1923, 1925, 1933a, 1933b), Coolidge (1931), Coxeter (1969), Hudson (1990), Salmon (1879), Semple & Roth (1949).
...we refer to a certain degree of informality of language, sacrificing precision to brevity, ..., and which has long characterized most geometrical writing.
...[The meaning] depends always on the context and is invariably assumed to be capable of unambiguous interpretation by the reader.