Words may have more than one meaning.
A dictionary
Yes, and this is referred to as being a context clue. Reading the context in which the word is being used, you can tell what the word means. You can infer the meaning of a word using context clues. The words around it are often hints as to what the word means.
It is called reading and comprehension. Reading alone is not sufficient to comprehend what you read. The ability to read is simply the ability to translate combinations of symbols, but comprehension comes from understanding what those combinations signify. When we read words we do not understand we look them up in a dictionary and infer their meaning from their context. Only by comprehending what we read can we fully understand the words that are written.
A Dictionary will give you the meaning of a word, its etymology and its roots, where a Thesaurus will give you words which have a similar (often the same) meaning and can be used in a similar context.
Depending on the context, 'known' can be a verb or an adjective. http://www.merriam-webster.com/dictionary/known
A primary source may contain outdated language or obscure terms that readers are not familiar with. A dictionary can provide definitions for these words, and context clues can offer additional information within the text to help readers understand the word's meaning in the specific context of the source.
Both a dictionary and a glossary entry provide definitions of terms or concepts. They may include pronunciation guides, part of speech categorization, and sometimes usage examples. Additionally, they often provide further explanation or context to help the reader understand the term better.
Context clues
You would likely be holding a dictionary or a glossary to look up the unfamiliar terms and understand their meanings in the context of the book.
The meaning of a homograph is usually determined by the context in which it appears. The surrounding words, the part of speech, and the overall message of the text can help clarify the intended meaning of the homograph. In some cases, looking up the word in a dictionary or seeking additional information may be necessary to understand its meaning in a specific context.
Looking up unfamiliar words in a dictionary is beneficial for expanding one's vocabulary and understanding the meaning of the word in context. However, it is not always necessary depending on the situation. When a word is hindering comprehension or its meaning is crucial, it is helpful to consult a dictionary, but for general understanding, context clues can suffice.
When you look up a word in the dictionary, you can find its meanings, pronunciations, parts of speech, and sometimes example sentences to show how it is used in context.
Alphabet
I am not entirely sure, in what context. But sometimes you simply need to get some information, to know what is real.
In this context, it is common. A specific dictionary, like the Webster's Dictionary, is proper.
A dictionary
A dictionary is very useful to everybody who uses language, especially to students, teachers, researchers. Its useful importance is to give definition/meaning to words in order to clarify and make a person understand the word he/she searches for in the proper context.