Once vs. Since

Onceadverb

(frequency) One and only one time.

Onceadverb

(temporal location) Formerly; during some period in the past.

Onceadverb

(mathematics) Multiplied by one: indicating that a number is multiplied by one.

Onceadverb

As soon as.

Onceadverb

(obsolete) At a future time.

Onceconjunction

As soon as; when; after.

Oncenoun

The ounce.

Onceadverb

For one time; by limitation to the number one; not twice nor any number of times more than one.

Onceadverb

At some one period of time; - used indefinitely.

Onceadverb

At any one time; - often nearly equivalent to ever, if ever, or whenever; as, once kindled, it may not be quenched.

Onceadjective

belonging to some prior time;

Onceadverb

on one occasion;

Onceadverb

as soon as;

Onceadverb

at a previous time;

Sinceadverb

From a specified time in the past.

Sincepreposition

From: referring to a period of time ending in the present and defining it by the point in time at which it started, or the period in which its starting point occurred.

Sincepreposition

Continuously during that period of time.

Sincepreposition

At certain points during that period of time.

Sinceadverb

From a definite past time until now; as, he went a month ago, and I have not seen him since.

Sinceadverb

In the time past, counting backward from the present; before this or now; ago.

Sinceadverb

When or that.

Sincepreposition

From the time of; in or during the time subsequent to; subsequently to; after; - usually with a past event or time for the object.

Sinceconjunction

Seeing that; because; considering; - formerly followed by that.