Picture two things lined up in the order you just named them: the 'former' is the one that came first, the 'latter' is the one further along — the second, later one. At root 'latter' just means 'the later of two', and everything else is that same idea of 'nearer the end'.
From the word’s history
'Latter' is from Old English lætra, the comparative of læt 'late' — so it literally means 'later, more toward the end'. The sense 'the second of two just mentioned' is recorded from the 1550s.
latter 來自古英語 lætra，是 læt（late，晚）的比較級——字面意思就是「比較晚的、比較靠後的」。這正好說明它的核心：兩者之中「後面那一個」。「剛提到的兩者中的第二個」這個用法約在 1550 年代出現。看清它就是 late 的比較級，就不會把它和 later 混掉：latter 講的是次序上的後者，不是時間上的晚點。
etymonline.com/word/latter
登入就可以看每一支怎麼連回核心畫面。
原始詞典資料3 筆記錄
以下是外部詞典記錄的用法，摘錄並精簡格式，我們還沒有寫成教學內容。上面的說明才是我們自己寫的；有些用法可能上面已經講過了。
latteradj/ˈlæt.ə(ɹ)/
- 1
Near (or nearer) to the end.
- the latter part of the century
- 2
In the past, but close (or closer) to the present time.
- In his latter years my dad became very absent-minded.
- Hath not navigation discovered in these latter ages, whole nations at the bay of Soldania […]?
latternoun/ˈlæt.ə(ɹ)/
- 1
Relating to or being the second of two items.
- The archaic past participle shapen is only used in misshapen, ill-shapen, and well-shapen (the latter two are much less common, though).
- the difference between reason and revelation, and in what sense the latter is superior
摘錄自 英文維基詞典 English Wiktionary，已精簡格式；依 CC BY-SA 4.0 授權使用，改動後的內容同樣以此授權提供。