1. (a.) Running between or among; intervening.

2. (a.) Not belonging to any particular season.

3. (a.) Said of diseases occurring in the course of another disease.

4. (n.) Something intervening.

Charlie McCarthy agency agent agential agentival agentive amidships ancilla appliance arbiter arbitrational arbitrative arbitrator assisting average banal broker center central channel coming between common conducive connection contact contrivance core creature deputy device distributor dummy dupe employable entrepreneur equatorial equidistant facilitating favoring forwarding front front man go-between going between halfway handmaid handmaiden handy helpful implement instrument instrumental instrumentality interagent interceder intercessional intercessor intercessory intercurrent interior interjacent interlocutory intermedial intermediate intermediate agent intermediator intermediatory intermedium internuncio interpleader intervener intervenient intervening interventional interventionist interventor jobber judge lever liaison link mean mechanism medial median mediary mediating mediative mediator mediatorial mediatory mediocre mediterranean medium mesial mesne mezzo mid middle middle-of-the-road middleman middlemost middling midland midmost midships midway midwife minion ministerial ministering ministry moderate mouthpiece negotiant negotiator negotiatress negotiatrix normal nuclear ombudsman ordinary organ pacificatory pawn plaything promoting puppet referee representative routine servant serviceable slave spokesman spokeswoman standard stooge subservient third party tie tool toy umpire useful usual vehicle wholesaler