Concepts are general ideas, not single concrete data. An utterance or a word denotes a meaning which may or may not exist in real life.
“The poet who says:

     “You frightened the polytheists so that the sperms 
     which are not yet born will fear Thee.” 

introduces a line of verse the first part of which has a meaning which is physically perceptible while the second half is not so. Utterances and sentences can be grasped, words can be explained but the meaning which the utterances implies is of value only if it can be sensed, imagined, or believed by the mind as something concrete and tangible. If it is so, it is called a concept with respect to the one who senses or imagines it; but it is not considered a concept with regard to the one who does not sense or imagine it. A student has to understand the meaning of sentences as they stand, not as he wants them to be, and should, at the same time perceive the reality of that meaning in his mind so that this meaning will become a concept. A concept is therefore the meaning which has a reality approached by the mind, whether this reality has an external sensible existence, or an existence whose acceptance is based on tangible things. A part from this, all the meanings of utterances and sentences are not termed concepts but mere data of information, these concepts are formed by associating reality with data of information, or linking data of information with reality.

The notions of Islam are concepts, not mere data of information, and being concepts they are significant in the various areas of life. They are not only an explanation of the things which abstract logic assumes to exist; but every concept of Islam has a reality which man can put his finger on, whether it is deep concept whose comprehension needs insight or a simple concept which can be understood easily; whether it is a tangible physical thing such as treatments, and general opinions, or invisible transcendental things such as divine secrets.