"Semantics is the systematic study of meaning in language. As a discipline, it is directed toward the determination of how humans reason with language, and more specifically, discovering the patterns of inference we employ through linguistic expressions."
Hogan, Patrick Colm. The Cambridge Encyclopedia of the Language Sciences. Cambridge University Press, 2011.
Below are some key (online) reference works for semantics.
The Wiley Blackwell Companion to Semantics by 
International Encyclopedia of the Social and Behavioral Sciences by 
The Routledge Handbook of Semantics by 
The Handbook of Contemporary Semantic Theory by 
Handbook of Logic and Language by For books on a specific language, use this format (replace 'French' with whichever language you are interested in):
Journal of Semantics covers all areas in the study of meaning, with a focus on formal and experimental methods. The Journal welcomes submissions on semantics, pragmatics, the syntax/semantics interface, cross-linguistic semantics, experimental studies of meaning (processing, acquisition, neurolinguistics), and semantically informed philosophy of language.
Natural Language Semantics journal is devoted to semantics and its interfaces in grammar, especially syntax. It publishes studies focused on linguistic phenomena, including quantification, negation, modality, genericity, tense, aspect, aktionsarten, focus, presuppositions, anaphora, definiteness, plurals, mass nouns, adjectives, adverbial modification, nominalization, ellipsis, and interrogatives.
Linguistics and Philosophy focuses on issues related to structure and meaning in natural language, as addressed in the semantics, philosophy of language, pragmatics and related disciplines.
The Journal of Logic, Language and Information explores the foundations of natural, formal, and programming languages, as well as the different forms of human and mechanized inference. It covers the logical, linguistic, and information-theoretic parts of the cognitive sciences.