<p>A quick Google search revealed that</p>

<blockquote>
  <p>Very generally, "leaves" refers to the pages of a book, as in the common phrase, "loose-leaf pages."</p>
  
  <p>A leaf is a single sheet bound in a book, and a leaf has two pages. (Source: <a href="https://biblio.co.uk/book_collecting_terminology/leaves-61.html" rel="nofollow noreferrer">Biblio</a>)</p>
</blockquote>

<p>A folded grouping of leaves is a "<a href="https://biblio.co.uk/book_collecting_terminology/%7BGLOBALS.SITE_BASE%7D/book_collecting_terminology/gatherings-71.html" rel="nofollow noreferrer">gathering</a>", so the left image under "leaf with 4 pages" in your question is actually a gathering of 4 leaves (8 pages).  The right hand image is a gathering of 2 leaves (4 pages)</p>

<p>Note that if you tear one leaf out of a bound book, as books are more commonly bound in gatherings, often one other leaf will also become loose, and maybe fall out — especially if the leaf torn out is in the centre of a gathering. But that is a separate leaf, not the other half of the same.</p>

CC BY-SA 4.0
2018-05-07T08:07:40.257Z
@CreationEdge - No.  If you have 8 numbered pages in 1 gathering you have 4 leaves.
Chris Rogers
CC BY-SA 4.0
2018-05-07T12:32:50.203Z
According to [U of Wisconsin](http://creative.uwp.edu/page/sheets-pages), the [English Language Stacke Exchange](https://ell.stackexchange.com/a/83229) and [wikipedia](https://en.wikipedia.org/wiki/Page_(paper)), a leaf has two sides and each side is considered one page.
Wimateeka
CC BY-SA 4.0
2018-05-07T13:57:16.140Z
Which matches what I said @Wimateeka
Chris Rogers
CC BY-SA 4.0
2018-05-05T06:42:40.953Z
2018-05-05T14:34:37.863Z
2018-05-05T14:34:37.863Z
Chris Rogers
<p>A co-worker asked a riddle that got me wondering about the anatomy of books and book binding methods.</p>

<p><strong>The Riddle:</strong></p>

<blockquote>
  <p>A leaf is torn from a paperback novel. The sum of the remaining page numbers is 15,000. What pages were torn out?</p>
</blockquote>

<p>According to the answer (and a lot of the internet), it claimed that a leaf: <br><br> <em>is a single sheet bound in a book, and a leaf has two pages</em>.</p>

<p>I thought this assumption was vague and that a leaf can either have two pages or four pages depending on how it is bound. This assumption also changes the answer of the riddle. </p>

<p><br>
<strong>Leaf with two page binding:</strong>
<br><a href="https://i.sstatic.net/2fWF9.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/2fWF9.png" alt="Two page binding"></a></p>

<p><br><strong>Leaf with four page binding:</strong>
<br><a href="https://i.sstatic.net/vjtZ3.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/vjtZ3.png" alt="Four page binding"></a></p>

<p><strong>Are both definitions of a <code>book leaf</code> correct? Or is there only one? Is one more commonly assumed than the other?</strong></p>

<paper><terminology><book-binding>
How many pages does a book leaf have?
Wimateeka
# How many pages does a book leaf have?

(Asked by: username_0 on 2018-05-01)

A co-worker asked a riddle that got me wondering about the anatomy of books and book binding methods.

**The Riddle:**

> A leaf is torn from a paperback novel. The sum of the remaining page numbers is 15,000. What pages were torn out?

According to the answer (and a lot of the internet), it claimed that a leaf:   
  
 *is a single sheet bound in a book, and a leaf has two pages*.

I thought this assumption was vague and that a leaf can either have two pages or four pages depending on how it is bound. This assumption also changes the answer of the riddle.

**Leaf with two page binding:**
  
[![Two page binding](https://i.sstatic.net/2fWF9.png)](https://i.sstatic.net/2fWF9.png)

**Leaf with four page binding:**
  
[![Four page binding](https://i.sstatic.net/vjtZ3.png)](https://i.sstatic.net/vjtZ3.png)

**Are both definitions of a `book leaf` correct? Or is there only one? Is one more commonly assumed than the other?**

**Tags:** paper, terminology, book-binding


---

## 1 answers

### Answer by username_1 on 2018-05-05. Score: 3 | Accepted answer

A quick Google search revealed that

> Very generally, "leaves" refers to the pages of a book, as in the common phrase, "loose-leaf pages."
>
> A leaf is a single sheet bound in a book, and a leaf has two pages. (Source: [Biblio](https://biblio.co.uk/book_collecting_terminology/leaves-61.html))

A folded grouping of leaves is a "[gathering](https://biblio.co.uk/book_collecting_terminology/%7BGLOBALS.SITE_BASE%7D/book_collecting_terminology/gatherings-71.html)", so the left image under "leaf with 4 pages" in your question is actually a gathering of 4 leaves (8 pages). The right hand image is a gathering of 2 leaves (4 pages)

Note that if you tear one leaf out of a bound book, as books are more commonly bound in gatherings, often one other leaf will also become loose, and maybe fall out — especially if the leaf torn out is in the centre of a gathering. But that is a separate leaf, not the other half of the same.

> **Comments:**
> **username_1**: @CreationEdge - No.  If you have 8 numbered pages in 1 gathering you have 4 leaves.  
> **username_0**: According to [U of Wisconsin](http://creative.uwp.edu/page/sheets-pages), the [English Language Stacke Exchange](https://ell.stackexchange.com/a/83229) and [wikipedia](https://en.wikipedia.org/wiki/Page_(paper)), a leaf has two sides and each side is considered one page.  
> **username_1**: Which matches what I said @username_0  

---

