Favourable means giving approval, or working in your favour. Either the verdict is good or the conditions are.
The approval sense covers reviews, opinions and comparisons, so a favourable review and comparing favourably with something both mean the judgement went well. The conditions sense covers weather, winds and terms, so a favourable wind pushes you along and favourable terms are ones you would accept. British English keeps the u and American English writes favorable. Its opposite, unfavourable, works in both senses.
1adjectivefavourableExpressing approval.
“The book had a favourable review in two papers.”
2adjectivehelpfulHelpful to your plans or interests.
“They waited for a favourable tide.”
Too few real examples of this word to estimate which sense is commonest.
Also accepted in games: favorable
Latin
favōrābilis
Old French
favorable
Middle English
favourable
English, today
favourable
From Middle English favourable, from Old French favorable, from Latin favōrābilis, from favor. by surface analysis, favour + -able.
Etymology from Wiktionary, CC BY-SA