use of a portion of a <#stamp>. Stamps were sometimes cut in half (or some other fraction) and placed on an envelope in an attempt to pay postage equal to one half (or other fraction) of the <#fv=face value> of the whole stamp. Occasionally an approved practice, sometimes tolerated, especially when there was a shortage of stamps in a needed <#denom=denomination>. Fractional usages are generally collected <#tied> on cover. One half of a stamp is known as a bisect.