This is the 3442nd most frequent Swedish word.
bly
Lead (metal).
Here, 'bly' refers to the elemental metal lead, used to describe the material of the pencil tip.
Pennans spets är gjord av bly.
The tip of the pencil is made of lead.
In this context, 'bly' again refers to the metal lead in relation to scientific or experimental procedures.
Hon fick bly i handen under experimentet.
She got lead on her hand during the experiment.
In this case, 'bly' is used figuratively to describe a shy or reserved demeanor, not the element.