The first is more or less along the lines that JRR used it—a phantom or ghost of a dead person.

第一种含义多少接近托尔金在他书中的用法——死人的鬼魂。

youdao

Their stern lines are groaning a lullaby air, A ghost in the cuddy, a gull on the spar; But never they whisper of journeys afar, Away from the roll of the sea.

听，浪花把摇篮曲低声吟唱， 那海鸥在回旋，幽灵在船舱， 但他们从不提及艰苦远航， 哦，远分开狂暴陆地。

youdao

On the rail network, Mr Hammond said night time "ghost trains" were being run in an attempt to keep lines open but "build up of ice on third rails across the Southeastern and Southern networks have led to loss of power and trains being stranded, causing severe delays and cancellations".

BBC: Labour berates 'complacency' of snow response

Panasonic wants that level of survivability in its SDHC and SDXC cards, and its new UHS-I-level SDAB and SDUB lines are tested for the kind of abuse that could see the camera give up the ghost first.

ENGADGET: Panasonic preps SD cards that survive heat, water and X-rays, will probably outlast you