中にも|なかにもnakanimo[1]atamadaka (head-high)

1. expression, adverbamong (other things); especially; particularly; inter alia; above all (else)
2. expression, adverbat the same time; simultaneously; at once; both

• SynonymとりわけNeutralEveryday word for 'especially' that pictures picking one out specially from the rest, as in 「とりわけ好きだ」.
• Synonym殊にことにNeutralHas a written flavour and stresses an exceptional degree, as in 「殊に美しい」.
• Synonym特にとくにNeutralThe everyday default for 'particularly', as in 「特に問題ない」.
• Synonym中でもなかでもNeutralClosest to the headword — 'especially among' — and the more frequently used of the two.
• Synonym格別かくべつNeutralStresses being out of the ordinary rather than singling one out from a group, as in 「格別の味」.
• Synonym特別とくべつNeutralAdjectival 'special', as in 「特別な日」; it never carries the 'among them' sense of the headword.
• SynonymなかんずくWrittenWritten and old-fashioned for 'especially, above all', as in 「なかんずく重要なのは」.
• Synonym別してべっしてWrittenWritten, old-fashioned and little used; say 「特に」 in everyday speech.
• SynonymわけてもWrittenWritten word for 'especially, above all', as in 「わけても彼は優秀だ」.
• Related一段いちだんNeutralStresses a further deepening of degree — 'even more' — as in 「一段と寒い」.
• Related格段かくだんNeutralStresses a large gap or marked difference in degree, as in 「格段に進歩」.
• Related別にべつにNeutralWith a following negative it means 'not particularly', as in 「別に何もない」.
• Related何はさておきなにはさておきNeutralAn idiom for 'before anything else', as in 「何はさておき乾杯」; it does not single one out from a group.
• RelatedわけてWrittenWritten, old-fashioned and little used; synonymous with 「別して」.
• RelatedひときわNeutralStresses standing out conspicuously from its surroundings, as in 「ひときわ目立つ」.
• RelatedひとしおNeutralCarries an emotional, reflective tone of 'all the more', as in 「喜びもひとしお」.
• Related立ててたててNeutralAn adverb for 'especially' but seldom used on its own; the common form is the compound 「取り立てて」.

For 'especially among many', 「中でも」 is the closest match and the more frequently used; 「中にも」 itself also appears in written prose and can mean 'at the same time, both'. In daily speech 「特に」 and 「とりわけ」 are the go-to words. 「就中」「別けても」「別けて」「別して」 are written or old-fashioned; 「一際」「一段」「格段」「一入」 stress degree or prominence rather than selection; 「特別」 is adjectival and never means 'among them', and 「何はさておき」 means 'first of all'.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 多おおくのもののうちで、特とくに、とりわけ。
2. 同時どうじに、一度いちどに、両方りょうほういっしょに。