nodes, what are true nodes?

are true nodes considered to be the the first sets of 7 leaves or would it be from the very bottom sets of 3 or in the middle at the 5's? im just wondering, i am topping my plant today hopefully and i just want to get it in the right spot, thank you for any info and thanks for reading

the first set of leaves from a seedling are called cotyledons, they do not count

the next set of leaves (first serated) are the first true node and every set after that is a node

the stem space between the nodes is called the internode

thanks for clearing that up for me, now is there any particular time of day i should top? i am growing outdoors in the ground, i.e. evening after the sun goes down or in the morn so it has the all day sun to help regrow asap.

doesn't matter to the plant as far as it is concerned an animal has taken a bite from it, it will distribute hormones to repair itself