1. apostrophe : a punctuation mark, and sometimes a diacritical mark, in languages that use the Latin alphabetand some other alphabets. In English it is used for several purposes:

• The marking of the omission of one or more letters (as in the contraction of do not to don't).
• The marking of possessive case (as in the eagle's feathers, or in one month's time).
• The marking of plurals of individual characters (e.g. p's and q's, three a's, four i's, and two u's, Oakland A's).

Apostrophe comes ultimately from Greek ἡ ἀπόστροφος [προσῳδία] (hē apóstrophos [prosōidía], "[the accent of] 'turning away', or elision"), through Latin and French.

The apostrophe looks the same as a closing single quotation mark, although they have different meanings. The apostrophe also looks similar to, but is not the same as, the prime symbol ( ′ ), which is used to indicate measurement in feet or arcminutes, as well as for various mathematical purposes, and the ʻokina ( ʻ ), which represents a glottal stop in Polynesian languages. Such incorrect substitutes as ´ (acute) and ` (grave) are common in unprofessional texts, where an ambiguous treatment of the apostrophe in digital typesetting (as explained below) is a major factor of this confusion.

2. When I Was One-and-Twenty : the informal name of an untitled poem by A. E. Housman, published in A Shropshire Lad in 1896. It is the thirteenth in a cycle of 63 poems. One of Housman's most familiar poems, it is untitled but often anthologised under a title taken from its first line. The Oxford Dictionary of Quotations includes fourteen of its sixteen lines. Housman's New York Times obituary mentioned the poem: "Typical of his lyrics is the poem which has thrilled the world where English is spoken." Its subject matter, "then and now" temporal perspective, meter, and narrative structure within each verse parallel those of William Butler Yeats' Down by the Salley Gardens, itself a reworking of The Rambling Boys of Pleasure.

※The content of the poem :

When I was one-and-twenty
I heard a wise man say,
‘Give crowns and pounds and guineas
But not your heart away;

Give pearls away and rubies
But keep your fancy free.’
But I was one-and-twenty,
No use to talk to me.

When I was one-and-twenty
I heard him say again,
‘The heart out of the bosom
Was never given in vain;
’Tis paid with sighs a plenty
And sold for endless rue.’
And I am two-and-twenty,
And oh, ’tis true, ’tis true.