A noun starting with H is house.
A verb starting with H is hear.
An adjective starting with H is heavy.
An adverb starting with H is hardly.
A food starting with H is hamburger.
A beverage starting with H is herbal tea.
An article of clothing starting with H is hat.
An mammal starting with H is hog.
A bird starting with H is hawk.
A reptile starting with H is Harlequin Gecko.
A fish starting with H is hammerhead shark.
A tree starting with H is hazelnut tree.
A plant starting with H is hibiscus.
A mineral starting with H is hematite.
A name starting with H is Hannah or Henri.
An actor starting with H is Hugh Grant.
A movie starting with H is Homeward Bound.
An historical figure starting with H is Hannibal (248-183 BC).
A country starting with H is Hondouras.
A city starting with H is Hartford, CT.
A river starting with H is the Helmand River, Afganistan.
A body of water starting with H is Hudson Bay.
A mountain range starting with H is the Himalayas.
A monument starting with H is US Holocaust Memorial Museum, Washington, DC.
A landmark starting with H is Hagia Sophia, Istanbul, Turkey.
20-letter words
histocompatibilities, homotransplantations, hydrochlorothiazides, hypercholesterolemia, hypercholesterolemic, hypercoagulabilities, hyperconsciousnesses, hyperparathyroidisms, hypersensitivenesses
21-letter words
hypercholesterolemias, hypersusceptibilities
22-letter words
hexamethylenetetramine
23-letter words
hexamethylenetetramines
Some 'An' words beginning with H are: hang, hanger, hand, handy, handle, handkerchief, Hanoi, Hank and Hannah...
Some positive words beginning with H are:happyhealthyheightenherohelpfulheavenhopeholyhavehugs
no such things
Hubble telescope
waggishwarmthwarpathwashwashclothwaspishwatchweakfishweakishwealthwherewithwretchwrathwristwatchwhiplashwhitishwhitewashwhooshwhichwithwitchwordsmithworthwreath
happyhardyharmonyhayhairyhazyherebyheredityhilarityhillbillyhillyhistoryheavyhickoryhockeyhokeyhomelyhomeyhominyhomilyhoneyhumanityhurryhusbandryhypocrisy
Quash
Five letter words starting with H and ending in H are:hatchhaughfeathheighheuchheughhitchhoochhunchhutchhumphhorahhotchharsh, heath.
haj hajj
I can only think of :headquarters
enough, establishWords beginning with e ending with h:eachepochetchextinguish
Hajib
Horn