實體疊在一起
最原始的一族，看得見摸得到：真的有兩個物體的邊壓在一起。
physically overlap · verb · C2
When two or more things overlap, part of one lies over part of the other.
交疊
核心畫面
Picture two roof tiles, or two sheets of paper laid down one after the other: the edge of one lies on top of the edge of the other. They are still two separate things, but there is a strip in the middle that belongs to both.
兩片屋瓦、或桌上兩張疊了一角的紙：一張的邊壓在另一張的邊上。它們仍然是兩張紙，沒有變成一張，但中間有一條「兩邊都佔到…更多收起
兩片屋瓦、或桌上兩張疊了一角的紙：一張的邊壓在另一張的邊上。它們仍然是兩張紙，沒有變成一張，但中間有一條「兩邊都佔到」的地帶。整個字的重點就在那條帶子——不是全部重合，也不是完全分開，而是「有一段共用」。之後所有的用法都是把這兩張紙換成別的東西：兩個主題、兩份工作、兩段時間，然後去看它們共用的是哪一塊。From the word’s history
Simply over- + lap: one thing laps over another, exactly the picture the word still carries.
這個字就是 over-（在上面）+ lap（搭上去、覆過去）拼出來的，沒有繞遠路：一個東西「搭過」另一個東西的邊。字面畫面和現代用法幾乎一模一樣，所以拆開來看反而最好記。
Wiktionary, "overlap" (over- + lap)
Four branches
內容有一部分相同
把兩張紙換成兩個「範圍」：主題涵蓋的內容、工作負責的事項，共用的那條帶子變成共同的部分。
partly the same (subjects) · verb · C2
When two subjects, ideas, or jobs overlap, they have some of the same things in them, but not all.
部分重疊
時間上還沒結束就開始
把那兩張紙換成兩段時間，共用的帶子就變成「兩件事同時都在進行」的那一段。
overlap in time · verb · C2
When two activities or times overlap, one is still going when the other begins.
時段重疊
共用的那一塊本身
名詞化：不看「疊」這個動作，而是指著中間那條帶子本身，還可以問它有多大。
amount of overlap · noun · C2
How much two activities, ideas, or things share the same space, time, or parts.
重疊
原始詞典資料9 筆記錄
以下是外部詞典記錄的用法，原文照列，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。
overlapverb/ˌəʊvəˈlæp/
- 1
To extend over and partly cover something.
- The mouse-mat overlapped the edge of the desk.
- 2
To co-occur, to happen at the same time.
- 3
To have an area, range, character or function in common.
- The two maps overlapped at the east and west edges.
- Memento unfolds over 22 scenes—or, more accurately, 22 strands of time, the main strand (in color) moving backward in increments, and another strand (in black and white) going forward, though the two overlap profoundly.
- 4
mathematicssciencesOf sets: to have some elements in common.
- The set (all men) overlaps the set (vegetarians).
- 5
biologygeneticsmedicineTo have some similar nucleotide sequences.
- 6
artartsAn illusion of depth is created when one object partially covers another.
overlapnoun/ˈəʊvəˌlæp/
- 1
Something that overlaps or is overlapped.
- 2
ball-gamesgameshobbiesa situation in the game where an attacking line has more players in it than the defensive line coming to meet it. The attacking side may exploit the overlap by using their superior numbers to break the opposition's defensive line. If attackers outnumber defenders by more than one player this is often termed a two man overlap or three man overlap, etc. If the attacking side fails to break through usually due to poor execution, they are said to waste an overlap.
- 3
businessinsuranceThe payment of a spouse's or other dependant's annuity benefits concurrently with the member's benefits, on death of the member during the guarantee period.
資料來源：英文維基詞典 English Wiktionary（CC BY-SA 4.0）。 原文照列，未經改寫。