Is there an alternate non-anatomical word to describe the action of "dilating"?

Is there a synonym for open other than dilate that describes the process of spreading open from a central point?

For example, when fire burns a hole in a piece of paper what would the paper be said to be doing? Or when a whirlpool begins to form, is there a word that describes the process of the water being drawn apart? And also what about the action of a camera shutter?

For all of these examples open would technically suffice because readers already have a grasp of these objects' mechanisms and there is no need for further explanation. But if I am trying to describe something new with which the reader has no previous familiarity, such as a futuristic machine, then open no longer adequately conveys my meaning without additional qualifying words or descriptions. We are used to opening things such as doors or boxes or drawers that involve either a hinge mechanism or some variation of two usually linear objects drawing apart from each other, and if I use this word I feel that I will have to struggle against these connotations.

Dilate perfectly captures what I am trying to describe but I do not want to use it because it is traditionally restricted to the action of an eye's pupil or some other sphincter and therefore may not come across well with readers.

I understand that there may be no other single word for this action but I wanted to put the question out there in case some rare or obscure word does exist.

Note: I prefer a single word substitute, but I am not opposed to suggestions of words that may be paired with open, such as spread or draw.

Example sentences:

So far there are two instances in a novel I am writing where I have needed a word to describe this motion. One example involves a wall opening, and the other involves a window opening. In both cases only a portion of the wall or window "retract" into themselves to create a hole or opening, and this without any noticeable bunching resulting around the edges.

  1. Up ahead the right wall ______ into an archway and Madeline hurried through.

  2. She was surprised when the glass ______ around her fingers, exposing them to the rain.

Edit:

It is a futuristic story where the walls and even windows are constructed from intricate biological machines which permit them to morph into various shapes seamlessly. But it is not the mechanism that I wish to describe, it is the motion, which is why I thought it unnecessary to digress into the mechanical minutiae. Dilate describes the motion.


Solution 1:

In case if you haven't realised it already, finding single words to accurately describe a specific situation is very hard and many a time, impossible. Why not just be a little more descriptive? Say what you want to say. The situation you have in mind doesn't necessarily have to be expressed by a single word.

  • Up ahead it seemed as if the walls on both sides were being hammered and bended and thinned out. The whole place metamorphosed into an archway, while Madeline hurried through.
  • She ran her fingers over the misty window. To her surprise, the glass gave way to her fingers and they passed through, exposing them to the rain. She stared in wonder at the glass as it spread out round her fingers.

  • The moment her finger touched the glass, a tiny hole formed at the spot, no bigger than a pinhead. As she went deeper into the glass, the hole kept enlarging/expanding from that point until it fit her finger completely.

Solution 2:

I still don't understand the example with the glass, but I will share some ideas about the first example.

First, let's focus on what's really going in dilation. In dilation, there is already a small opening, and when it dilates, it gets bigger. If you start with something that looks like a smooth wall, and it appears to morph into a doorway, then I don't think anything is actually dilating.

I will work from what you said about intricate biological machines which morph into various shapes seamlessly.

Morph would work, but I can see that you would prefer something more subtle. Shift would be nice, but I suspect that word has been a bit overused in the genre you're working in. So here are a few words in the target area:

  • reshape
  • convert
  • transform
  • recast
  • reform
  • transmute
  • part
  • spread

You can also use some slightly farther afield word such as

  • toggle
  • retune
  • permute

But Peter, I see no reason not to repurpose some even less related word to convey what you have in mind. You are creating a tangible world that is different from ours; you may also create a vocabulary as you go along. Some examples of this repurposing approach:

  • tune
  • swish
  • door (use as a verb, e.g. "the wall ahead doored into an archway")

The third and last way to go about it is to create a brand new word, for example (these are all verbs):

  • re-just (from adjust)
  • sesame (from Open, Sesame; past tense might be sesame'ed)
  • mod (past tense modded)
  • diff (from make different)

These last four examples are not particularly good -- they are just provided to free you up in your thinking.

Solution 3:

For your first example, I would use dilate - I've seen it used in examples for doors before, especially in science fiction. Do a Google search for the phrase and you'll see it is not only used, it's a canonical example from Heinlein about evoking the future simply.

For your second example, I think I'd use something that would emphasize the motion of the glass away from the fingers (a motion which is not necessarily strictly circular), like "withdrew". That seems to capture the inherent and presumably intentional creepiness of the motion under the hand.

Solution 4:

You might use divaricate, which means

  • to spread apart
  • to diverge widely

"divaricate one's fingers"

It's also used in botanical sense as to diverge at a wide angle; to branch off; forked. It describes the motion of not only spreading but separating too. The particles of the door/glass separately diverging (or branching off) to morph into an archway.

  1. [...] the wall divaricated (branching/spreading widely from a point) into an archway and Madeline hurried through.
  2. [...] when the glass divaricated (separates and spreads) around her fingers, exposing them to rain.'

On a technical note, also consider

centrifugal

proceeding or acting in a direction away from a center or axis.

It's verb is

centrifugate

to drive out centrifugally

"the wall centrifugates into an archway"