Significado de "Arm in arm"

Para essa frase, li algumas traduções como mão dadas e braços dados, mas no texto que encontrei a mesma se referia a 2 homens e não me parece ser o caso. A frase também poderia representar aqueles abraços de duas pessoas lado a lado com os braços por cima do ombro do outro? (aliás, tem alguma frase ou palavra em português pra se referir a isso? ^^)

Segue frase que me originou a dúvida:

Arthur went down on his knees and kissed Lucy for the last time. Then he and Quincey walked, arm in arm, out into the sunlight.

Can be "linking arms", it could be romantically but not necessarily.

https://i0.wp.com/i.dailymail.co.uk/i/p ... .jpg?w=620
https://media.mnn.com/assets/images/201 ... x0_q80.jpg
http://www.victorianweb.org/art/illustr ... lby/60.jpg
http://gordonbugbee.com/images/arm_in_arm%20sm.jpg
http://www.gettyimages.com/detail/photo ... N_Redirect
https://buidln.clipdealer.com/001/882/1 ... in-arm.jpg

The second option is that they are "arm in arm" figuratively, that is, in collusion with/in concert with one another (a group) or with each other (two people).

In collusion would be that they would be ally or make some kind of agreement to do something in secret, generally some kind of cooperation in illegal or secretly ways. One example could be to deceive or cheat someone else.
In legalese, it could be to fix prices, agreement for not competing for customers, etc. It can seem thought as a sort of conspiration.