There are a total of 162 8-letter words containing 'yn', and the number may vary in different dictionaries. You can specify the dictionary and order.

• adynamia ₁₅
• adynamic ₁₈
• aerodyne ₁₂
• amboynas ₁₇
• anodynes ₁₃
• anodynic ₁₆
• aroynted ₁₂
• asyndeta ₁₂
• autodyne ₁₃
• awayness ₁₄
• busyness ₁₅
• cynicism ₂₀
• cynodont ₁₆
• cynosure ₁₅
• didynamy ₁₈
• duvetyne ₁₇
• duvetyns ₁₇
• dynamics ₁₈
• dynamise ₁₅
• dynamism ₁₈
• dynamist ₁₅
• dynamite ₁₅
• dynamize ₂₄
• dynastic ₁₅
• dynatron ₁₃
• eryngium ₁₇
• eryngoes ₁₃
• ethynyls ₁₆
• grayness ₁₃
• greyness ₁₃
• gwyniads ₁₇
• gynaecea ₁₆
• gynaecia ₁₆
• gynandry ₁₇
• gynarchy ₂₀
• gynecium ₂₀
• gynecoid ₁₇
• gyniatry ₁₅
• gynoecia ₁₆
• hologyny ₁₈
• hypogyny ₂₂
• keynoted ₁₆
• keynoter ₁₅
• keynotes ₁₅
• langsyne ₁₅
• laryngal ₁₅
• larynges ₁₄
• larynxes ₁₉
• lipsyncs ₁₈
• lynchers ₁₇
• lynchets ₁₇
• lynching ₂₀
• lynchpin ₂₁
• megadyne ₁₇
• misogyny ₁₈
• monogyne ₁₇
• monogyny ₁₉
• mynheers ₁₆
• perigyny ₁₈
• polygyne ₁₉
• polygyny ₂₁
• polynyas ₁₇
• postsync ₁₇
• reynards ₁₂
• spryness ₁₄
• synagogs ₁₅
• synanons ₁₃
• synapsed ₁₅
• synapses ₁₄
• synapsid ₁₅
• synapsis ₁₄
• synaptic ₁₇
• synarchy ₁₈
• synastry ₁₃
• syncarps ₁₇
• syncarpy ₁₉
• synching ₁₉
• synchros ₁₆
• syncline ₁₆
• syncopal ₁₈
• syncopes ₁₇
• syncopic ₂₀
• syncytia ₁₆
• syndeses ₁₂
• syndesis ₁₂
• syndetic ₁₅
• syndical ₁₆
• syndrome ₁₅
• synectic ₁₇
• synergia ₁₃
• synergic ₁₆
• synergid ₁₄
• synfuels ₁₆
• syngamic ₁₉
• syngases ₁₃
• synonyme ₁₇
• synonyms ₁₇
• synonymy ₁₉
• synopses ₁₄
• synopsis ₁₄
• synoptic ₁₇
• synovial ₁₆
• synovias ₁₅
• synsacra ₁₄
• syntagma ₁₆
• syntagms ₁₆
• syntaxes ₁₈
• syntenic ₁₅
• synthase ₁₃
• synthons ₁₄
• synthpop ₁₉
• syntones ₁₂
• syntonic ₁₅
• syntypes ₁₆
• wrynecks ₂₁
• ynglings ₁₇
• baynoddy ₁₈
• ladyness ₁₂
• propynes ₁₅
• sphynxes ₂₃
• syngenic ₁₄
• synkarya ₁₈
• asynergy ₁₅
• cagyness ₁₄
• capitayn ₁₅
• cynanche ₁₈
• darrayns ₁₂
• demaynes ₁₄
• desyning ₁₃
• digynian ₁₃
• digynous ₁₃
• endodyne ₁₃
• esloyned ₁₂
• esloynes ₁₁
• essoynes ₁₁
• fynboses ₁₆
• gamyness ₁₄
• gyrodyne ₁₆
• homelyns ₁₆
• homodyne ₁₇
• lynxlike ₂₂
• paynimry ₁₈
• polynias ₁₃
• poynting ₁₄
• proyning ₁₄
• queynies ₂₀
• sdayning ₁₃
• stayning ₁₂
• synangia ₁₂
• synanthy ₁₇
• synaphea ₁₆
• synaptes ₁₃
• syndeton ₁₂
• syndings ₁₃
• synechia ₁₆
• synedria ₁₂
• syngraph ₁₇
• synodals ₁₂
• syntexis ₁₈
• syntonin ₁₁
• trayning ₁₂
• uncoyned ₁₄

There are 162 8-letter words containing yn in the well-known word game dictionary, 110 in the Scrabble US (US/Canada/Thailand - TWL/NWL) dictionary, and 151 in the Scrabble UK (International - SOWPODS/CSW) dictionary, and 116 in the Words with Friends (WWF) dictionary.