Monolingual dictionaries : They may be useful for a translator to understand an item, a concept and to get detailed view of the term. Each word in a monolingual dictionary is defined minutely and supplemented with other near synonymes in the language, to make the meanings clear.

Bilingual dictionaries : These dictionaries are very useful, though not the only tools for technical translation. It is a tool that helps a translator find the corresponding target language unit for the SL item, thereby facilitating rendering and recreating a text in the target language. Bilingual dictionaries - both general and specialized - differ from monolingual ones in offering translation equivalents instead of giving long definitions and explanations. Long and exhaustive definitions are desirable for monolingual dictionaries, but can be frustating and misleading in a bilingual dictionary. Definitions and explanations may help a translator in understanding a concept, but may not be much useful in finding a corresponding word or a replacement of the source language item. Bilingual lexicographers resort to definitions only when a source language word has no equivalent word in target language or when the source language designatum is absent in the target language. Generally, translators turn to bilingual dictionary to find a suitable translation equivalent in the target language. For more information on the culture-specific terms the translator is well advised to refer to a good monolingual dictionary and / or an encyclopaedia.

     Translation equivalent does not, however, mean identical or absolute equivalent, as it is difficult if not impossible, to get a word in target language that is equivalent to a source language word in all respects - denotation, connotation and range of application. What the bilingual dictionaries list as equivalents are only partial equivalents, also known as translational equivalent, because these are ready-made target language units that can easily be replaced in translation and fitted in a sentence. Finding translation equivalents in a target language is a "job per excellence". It makes translators' job easier, provided the dictionary is a good one, devoid of linguistic ambiguities.

     A bilingual lexicographer, while listing translation equivalents is guided by the principle of economy, precision and accuracy, which in bilingual dictionaries is achieved by providing glosses, labels, registers and illustrations and usages, etc. In fact translation equivalents require glosses much more than definitions, which however are explanatory. By glosses, we mean 'words', in terms of restriction or extension of meaning or its usage, and these are a very important and effective method of providing meaning discrimination in a bilingual dictionary, more so if it is aimed at the target language. This helps a translator pick up the right word with the right sense and if necessary "stretch" the language at the text level, for effective communication of the message. General bilingual dictionaries are the most important aid for translation in general. A technical translator, however, may need - besides a bilingual dictionary - some subject dictionaries as well.

Thesaurus : Thesaurus is what we would call concept dictionaries. The words in a thesaurus are classified not according to the sound or morphology, but according to their signification. The arrangement of items in terms of concepts provides the entire paradigm or semantic field. In the absence of satisfactory universal classificatory system, it may not be a perfect tool for translation but is nonetheless useful in understanding the concepts, their formations and relations within the system.