Hum [verb]

What once seemed so rare and arcane has now become a sad hum in the background — the contrails of an administration that the country may take a generation to shake.

Over the past four years, there has been a constant, low-level hum of rumors about the status of Apple’s automotive ambitions, with a major partnership announcement always supposedly just months or weeks away.

Think about the general din of being inside an airplane or hum of an air conditioning unit, with active noise cancellation all that disappears.

Those in charge of maintenance should have their tasks made easier by Health and Usage Monitoring Systems, or HUMS.

The hum is generated by the rapid jitters of particles that make up the hot object.

The hum of earnest or glad voices here contrasted strongly with silence and meditation there.

The girl began to hum, as she powdered her nose with a white glove, lying in a powder box.

She fell to her task again, only now she began to hum softly, thus shutting me off entirely.

In a moment Skipper Worse was wide awake, and began to hum, as she moved her fingers along the lines.

Matt listened to the steady hum of the Comet's twin cylinders with an exultation he could not conceal.