Attention, study, concentration, application can mean the direct focusing of the mind on something, especially on something to be learned, worked out, or dealt with.
Attention is applicable to the faculty or power as well as to the act. Since the word carries no inherent implications about the power or the act or of the length of the latter’s duration, it usually requires qualifying words or phrases.
Study stresses continuity and closeness of attention; it usually also implies an aim such as the acquisition of knowledge, or the analysis of something that is complex or confusing, or the working out of a plan (as for action) or of a design (as for a book).
Concentration emphasizes the centering of the attention on one thing to the exclusion of everything else.
Application usually implies persistence in fixing one’s attention, and diligence and assiduity in the performance of all that is required; it suggests therefore a virtue won by effort and sheer force of will rather than (as with concentration) a power that has its origin in one’s temperament or is the result of profound interest.