【Discord】 , 【strife】 , 【conflict】 , 【contention】 , 【dissension】 ,  【difference】 , 【variance】 mean a state or condition marked by disagreement and lack of harmony or the acts or circumstances which manifest such a state or condition.

【Discord】  implies not only a want of harmony or of concord between persons or between things but also, usually, a positive clashing which manifests itself in personal relations by quarreling, factiousness, or antagonism, in relations between sounds by a resulting dissonance or unpleasant noise, and in relations between other things that are incongruous or incompatible by creating unpleasant impressions or mental disturbance.

【Strife】 throws the emphasis on a struggle for superiority rather than on the incongruity or incompatibility of the persons or things that disagree.

It applies chiefly to relations between persons, and when used in reference to things it is nearly always figurative. Also, the term may imply any of widely different motives for the struggle (as rivalry, emulation, 【difference】  in opinion, disagreement, deep antagonism, or violent hostility).

【Conflict】 (see also CONTEST) implies a clashing and a struggle, but it stresses not the aim or end but the process, the uncertainty of the outcome, or the trials, difficulties, or torments it involves. In this sense the term may apply to actual battles or wars, but usually it applies to a mental, moral, or spiritual state of a person or group of persons or to its outward manifestations.

The term is also used in a milder sense to imply an incompatibility between or the impossibility of reconciling two things which come together at the same time or upon the one person.

【Contention】 may be used in place of 【strife】 in any of the senses of the latter word; more often it applies to 【strife】 that manifests itself in quarreling, disputing, or controversy; it may even be applied to a condition of affairs marked by altercations or brawls .

【Dissension】 may imply 【discord】 or 【strife】  between persons or parties, but it lays greater stress on a breach between them than do any of the preceding words; thus, to say that there is 【dissension】 in a church or political party is to imply that it is broken up into contentious or discordant factions.

【Difference】 (often in the plural) and  【variance】 usually imply a clash between persons or things owing to dissimilarity in opinion, character, or nature that makes for 【discord】 or 【strife】 . The terms may also suggest apparent or actual incompatibility or impossibility of reconciliation.