user47871: Can analog pins be defined by their digital pin number, and be used for analog purposes?
For example, instead of defining A0 for a pinout with the Uno, it could be 14?
Where is this documented? Is there a PDF type manual related to this, but not so low level to get into the ATmega chip?

https://www.arduino.cc/en/Hacking/PinMapping2560

user4143: 
For example, instead of defining A0 for a pinout with the Uno, it could be 14?

Yes. In fact A0 is just a placeholder for the number 14.
For all these things you should look in the pins_arduino.h file (Arduino\variants\wifio) for any variant you are interested in. That's where most of these symbols are defined. For example:
#define PIN_A0   (14)                                                                                   
#define PIN_A1   (15)                                                                                   
#define PIN_A2   (16)                                                                                   
#define PIN_A3   (17)                                                                                   
#define PIN_A4   (18)                                                                                   
#define PIN_A5   (19)                                                                                   
#define PIN_A6   (20)
#define PIN_A7   (21)

static const uint8_t A0 = PIN_A0;
static const uint8_t A1 = PIN_A1;
static const uint8_t A2 = PIN_A2;
static const uint8_t A3 = PIN_A3;
static const uint8_t A4 = PIN_A4;
static const uint8_t A5 = PIN_A5;
static const uint8_t A6 = PIN_A6;
static const uint8_t A7 = PIN_A7;

Incidentally, on the Uno you can also just use 0 for A0 with analogRead().

47871: <p>Can analog pins be defined by their digital pin number, and be used for analog purposes?</p>
<p>For example, instead of defining <code>A0</code> for a pinout with the Uno, it could be <code>14</code>?</p>
<p>Where is this documented? Is there a PDF type manual related to this, but not so low level to get into the ATmega chip?</p>
<p><a href="https://i.stack.imgur.com/As4Tn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/As4Tn.png" alt="enter image description here" /></a></p>
<p><a href="https://www.arduino.cc/en/Hacking/PinMapping2560" rel="nofollow noreferrer">https://www.arduino.cc/en/Hacking/PinMapping2560</a></p>
 4143: <blockquote>
<p>For example, instead of defining A0 for a pinout with the Uno, it could be 14?</p>
</blockquote>
<p>Yes. In fact A0 is just a placeholder for the number 14.</p>
<p>For all these things you should look in the <code>pins_arduino.h</code> file (Arduino\variants\wifio) for any variant you are interested in. That's where most of these symbols are defined. For example:</p>
<pre><code>#define PIN_A0   (14)                                                                                   
#define PIN_A1   (15)                                                                                   
#define PIN_A2   (16)                                                                                   
#define PIN_A3   (17)                                                                                   
#define PIN_A4   (18)                                                                                   
#define PIN_A5   (19)                                                                                   
#define PIN_A6   (20)
#define PIN_A7   (21)

static const uint8_t A0 = PIN_A0;
static const uint8_t A1 = PIN_A1;
static const uint8_t A2 = PIN_A2;
static const uint8_t A3 = PIN_A3;
static const uint8_t A4 = PIN_A4;
static const uint8_t A5 = PIN_A5;
static const uint8_t A6 = PIN_A6;
static const uint8_t A7 = PIN_A7;
</code></pre>
<p>Incidentally, on the Uno you can also just use <code>0</code> for A0 with <code>analogRead()</code>.</p>
