3 letters:
arc, ark

4 letters:
bark, dark, harc, hark, lark, marc, mark, merc, narc, parc, park, sark

5 letters:
6park, amarc, asarc, barch, barke, bbsrc, charc, chark, clark, darke, dmarc, flark, glark, harch, harke, karch, larke, lharc, marke, narch, ozark, parke, pparc, quark, saarc, sharc, slark, smarc, snark, sparc, spark, starc, stark, usarc, yarke

6 letters:
3dmark, agmark, anarch, avmark, barque, belarc, bjarke, bomarc, clarke, d-mark, demarc, demark, duparc, embarc, embark, empark, enarch, endark, esmark, igarch, imbark, impark, indarc, konark, lamark, lanark, marque, monarc, musarc, numark, parque, ramark, remark, sparke, squark, starck, starke, triarc, unmark, uppark, usmarc

7 letters:
airpark, altmark, aramark, ardvark, bevmark, bismark, calmark, carpark, commark, danmark, daymark, denmark, disbark, dispark, earmark, ecomark, finmark, forearc, furmark, futharc, genarch, geopark, hedmark, lamarck, lexmark, lugmark, mismark, monarch, mudlark, neumark, newmark, oakmark, ostmark, poldark, premark, pugmark, raymark, re-mark, sanmark, seamark, sigarch, simpark, skylark, stelarc, surmark, titlark, toparch, triarch, unimarc, waymark, xerarch, zoopark

8 letters:
aardvarc, aardvark, ballpark, baresark, bismarck, boshvark, car-park, caremark, catshark, cellmark, chempark, chilmark, cyberark, danemark, datemark, digimarc, ectosarc, endosarc, equimark, ethnarch, fatah-rc, fatshark, finnmark, footmark, goldmark, gymshark, hallmark, hashmark, hierarch, highmark, hoofmark, hydrarch, irenarch, kitemark, lamarque, landmark, lindmark, lovemark, lundmark, man-mark, minipark, mintmark, moorpark, myriarch, oligarch, outmarch, pathmark, pentarch, perisarc, petrarch, phylarch, pockmark, poshmark, postmark, reimbark, remarque, sawshark, semidark, sitzmark, skidmark, stenmark, swanmark, taxiarch, telemark, tetrarch, tidemark, transarc, treyarch, trustarc, twitlark, westmarc, westmark, woodlark, wordmark

9 letters:
aard-vark, antiquark, baumstark, benchmark, birthmark, boschvark, brandmark, brownmark, checkmark, chiliarch, coenosarc, crossmark, date-mark, dinoshark, disembark, disimpark, dodecarch, eirenarch, frogmarch, gameshark, graustark, hall-mark, hexaquark, hoof-mark, intermark, interpark, kybunpark, landshark, loanshark, matriarch, mauerpark, mediamark, metalmark, mid-march, patriarch, pressmark, skatepark, southmark, spreepark, squirarch, stylemark, surfshark, torchmark, touchmark, trademark, transmark, transpark, uckermark, underdark, vandemark, watermark, waterpark, wireshark

10 letters:
#hash-mark, angelshark, angle-park, assay-mark, bench-mark, briefmarke, cimeliarch, fingermark, frog-march, futuremark, hansa-park, heresiarch, leptoquark, lightspark, mandriarch, meadowlark, pentaquark, pitch-dark, reichsmark, steiermark, tetraquark, trade-mark, vandermark, vondelpark, wondermark

11 letters:
bizaardvark, countermark, deutschmark, double-park, durgin-park, ecclesiarch, europa-park, grooveshark, gymnasiarch, hersheypark, housemarque, hundertmark, magpie-lark, middlemarch, mysteriarch, servicemark, symposiarch, westermarck

12 letters:
deutschemark

13 letters:
borussia-park, malkastenpark, parallel-park, question-mark

14 letters:
?question-mark, kimberly-clark, vanderbijlpark

15 letters:
crystaldiskmark

16 letters:
glow-in-the-dark

3 letters:
irk

4 letters:
perk, lurk, fork, dirk, pork, york, jerk, turk, murk, kirk, cork, work, bork, dork

5 letters:
burke, shirk, stork, quirk, smirk, stirk, clerk, chirk, klerk, merck

6 letters:
torque, cirque, rework, uncork

7 letters:
berserk

8 letters:
overwork

10 letters:
salesclerk