How do you call the things on the top of the fence?

There is a term "security fence spikes" (google the term) which refers to separate strips of metal with spikes on, which can be added to existing fences and walls for the same purpose. I don't think there is a separate term for ones in which the "spikes" are already part of the fence. I'd just call it a "security fence" to distinguish it from a "normal" fence. (However, many fences used for security don't have spikes on - the existence and height of the fence is considered enough.) Then you can add Trochfa's suggestions if you need to specify the geometry of the top part.

Both fences have a top edge which has sharp points sticking up from the metal lattice - these are there to make it hard/dangerous to climb over and they deter thieves from trying to climb over. The sharp points have the same function as the spikes you found in your dictionary - and we can call them spikes.There is a term "security fence spikes" (google the term) which refers to separate strips of metal with spikes on, which can be added to existing fences and walls for the same purpose. I don't think there is a separate term for ones in which the "spikes" are already part of the fence. I'd just call it a "security fence" to distinguish it from a "normal" fence. (However, many fences used for security don't have spikes on - the existence and height of the fence is considered enough.) Then you can add Trochfa's suggestions if you need to specify the geometry of the top part.

Link to Zishen

I need a word or words for fences which invoke a feeling of 'looking through bars'.

Take a popular type of fence around properties: typically black, spear-like bars with pointy tops, with a couple of horizontal rails: picket fence.

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I went through a couple of thesauruses and there seems to be precious little synonyms without going into things like barricades and ditches. The phrase I have in mind is: "I stare at/through the rusting railing" and I want to emphasise the aspect of an obstacle making something visible, but unreachable. I chose railing for rhyming potential, and while it can apparently be of any height, I fear it has wrong connotations: of something much shorter in general, with the focus on a single horizontal top rail like along stairs, which would severely clash with my intent.

Now, the fact that it is a property fence has been already established, so if saying something like 'looking through the pickets' or whatsies doesn't sound unnatural, it could certainly do. Sorry for being picky, but, one, I simply cannot rhyme 'fence' with something that would fit my purpose and, two, it is somewhat abstract and I don't think that it has an immediate visual association I am going for.

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