-ability can be added to conceive to make conceivability, which is a noun. Conceivableness is also a noun.

-ability can be added to conceive to make conceivability, which is a noun. Conceivableness is also a noun.

Yes, it is entirely possible for siblings to be separated by several decades. The main factor to consider though in this is the age of the mother and the conceivability of them bearing a child at the time the elder was born. ---- If a woman has a child at 18 and a child at 38, those siblings will be separated by 20 years. Both are quite plausible. It is also likely that there will be other children in between. A gap of 20 years between adjacent siblings is unusual.

There are no words in the English language that begin with 'ceiv', although there are 91 that contain it.

apperceive

archdeceiver

conceivability

conceivable

conceivableness

conceivably

conceive

conceiver

coreceiver

deceivability

deceivable

deceivableness

deceivably

deceive

deceiver

deceiving

deceivingly

disdeceive

foreconceive

imperceivable

imperceivableness

imperceivably

imperceived

imperceiverant

inconceivability

inconceivable

inconceivableness

inconceivably

interreceive

malconceived

misconceive

misconceiver

misperceive

misreceive

nonconceiving

nondeceivable

nonreceiving

perceivability

perceivable

perceivableness

perceivably

perceivance

perceivancy

perceive

perceivedly

perceivedness

perceiver

perceiving

perceivingness

preconceivable

preconceive

preconceived

predeceive

predeceiver

preperceive

prereceive

prereceiver

receivability

receivable

receivables

receivablness

receival

receive

received

receivedness

receiver

receivership

reconceive

redeceive

reperceive

transceiver

unapperceived

unconceivable

unconceivableness

unconceivably

unconceived

unconceiving

undeceivable

undeceivableness

undeceivably

undeceive

undeceived

undeceiver

undeceiving

underreceiver

unmisconceivable

unperceived

unperceivedly

unreceivable

unreceived

unreceiving

apperceive

archdeceiver

calceiform

ceibo

ceil

ceile

ceiler

ceilidh

ceiling

ceilinged

ceilingward

ceilingwards

ceilometer

Cocceian

Cocceianism

commonplaceism

conceit

conceited

conceitedly

conceitedness

conceitless

conceity

conceivability

conceivable

conceivableness

conceivably

conceive

conceiver

coniceine

coreceiver

croceic

crocein

croceine

deceit

deceitful

deceitfully

deceitfulness

deceivability

deceivable

deceivableness

deceivably

deceive

deceiver

deceiving

deceivingly

disdeceive

doughfaceism

Dromiceiidae

Dromiceius

Erinaceidae

fluorescein

forconceit

foreconceive

Gallinacei

glaceing

haecceity

imperceivable

imperceivableness

imperceivably

imperceived

imperceiverant

inconceivability

inconceivable

inconceivableness

inconceivably

interreceive

lardacein

malconceived

misconceive

misconceiver

misperceive

misreceive

narceine

niceish

nonconceiving

nondeceivable

nonreceipt

nonreceiving

orcein

panaceist

pearceite

perceivability

perceivable

perceivableness

perceivably

perceivance

perceivancy

perceive

perceivedly

perceivedness

perceiver

perceiving

perceivingness

Ploceidae

ploceiform

Ploceinae

preconceivable

preconceive

preconceived

predeceive

predeceiver

preperceive

prereceipt

prereceive

prereceiver

priceite

Princeite

receipt

receiptable

receiptless

receiptor

receipts

receivability

receivable

receivables

receivablness

receival

receive

received

receivedness

receiver

receivership

reconceive

redeceive

reperceive

romanceish

romanceishness

transceiver

unapperceived

unceiled

unceilinged

unconceited

unconceivable

unconceivableness

unconceivably

unconceived

unconceiving

undeceitful

undeceivable

undeceivableness

undeceivably

undeceive

undeceived

undeceiver

undeceiving

underceiling

underreceiver

unmisconceivable

unperceived

unperceivedly

unreceipted

unreceivable

unreceived

unreceiving

urceiform